diff --git a/cotisations/acl.py b/cotisations/acl.py
index 4e147a82..aa98c32a 100644
--- a/cotisations/acl.py
+++ b/cotisations/acl.py
@@ -27,6 +27,7 @@ Here are defined some functions to check acl on the application.
 """
 from django.utils.translation import ugettext as _
 
+
 def can_view(user):
     """Check if an user can view the application.
 
@@ -38,4 +39,7 @@ def can_view(user):
         viewing is granted and msg is a message (can be None).
     """
     can = user.has_module_perms('cotisations')
-    return can, None if can else _("You don't have the rights to see this application.")
+    if can:
+        return can, None
+    else:
+        return can, _("You don't have the rights to see this application.")
diff --git a/cotisations/forms.py b/cotisations/forms.py
index d0a891bd..4414de3e 100644
--- a/cotisations/forms.py
+++ b/cotisations/forms.py
@@ -20,7 +20,7 @@
 # with this program; if not, write to the Free Software Foundation, Inc.,
 # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 """
-Forms for the 'cotisation' app of re2o. It highly depends on 
+Forms for the 'cotisation' app of re2o. It highly depends on
 :cotisations:models and is mainly used by :cotisations:views.
 
 The following forms are mainly used to create, edit or delete
@@ -38,7 +38,7 @@ from __future__ import unicode_literals
 from django import forms
 from django.db.models import Q
 from django.forms import ModelForm, Form
-from django.core.validators import MinValueValidator,MaxValueValidator
+from django.core.validators import MinValueValidator, MaxValueValidator
 from django.utils.translation import ugettext as _
 from django.utils.translation import ugettext_lazy as _l
 
@@ -47,7 +47,8 @@ from preferences.models import OptionalUser
 from users.models import User
 
 from re2o.field_permissions import FieldPermissionFormMixin
-from re2o.mixins import FormRevMixin 
+from re2o.mixins import FormRevMixin
+
 
 class NewFactureForm(FormRevMixin, ModelForm):
     """
@@ -109,12 +110,16 @@ class CreditSoldeForm(NewFactureForm):
     montant = forms.DecimalField(max_digits=5, decimal_places=2, required=True)
 
 
-class SelectUserArticleForm(FormRevMixin, Form):
+class SelectUserArticleForm(
+        FormRevMixin, Form):
     """
-    Form used to select an article during the creation of an invoice for a member.
+    Form used to select an article during the creation of an invoice for a
+    member.
     """
     article = forms.ModelChoiceField(
-        queryset=Article.objects.filter(Q(type_user='All') | Q(type_user='Adherent')),
+        queryset=Article.objects.filter(
+            Q(type_user='All') | Q(type_user='Adherent')
+        ),
         label=_l("Article"),
         required=True
     )
@@ -127,10 +132,13 @@ class SelectUserArticleForm(FormRevMixin, Form):
 
 class SelectClubArticleForm(Form):
     """
-    Form used to select an article during the creation of an invoice for a club.
+    Form used to select an article during the creation of an invoice for a
+    club.
     """
     article = forms.ModelChoiceField(
-        queryset=Article.objects.filter(Q(type_user='All') | Q(type_user='Club')),
+        queryset=Article.objects.filter(
+            Q(type_user='All') | Q(type_user='Club')
+        ),
         label=_l("Article"),
         required=True
     )
@@ -140,6 +148,7 @@ class SelectClubArticleForm(Form):
         required=True
     )
 
+
 # TODO : change Facture to Invoice
 class NewFactureFormPdf(Form):
     """
@@ -147,9 +156,18 @@ class NewFactureFormPdf(Form):
     """
     paid = forms.BooleanField(label=_l("Paid"), required=False)
     # TODO : change dest field to recipient
-    dest = forms.CharField(required=True, max_length=255, label=_l("Recipient"))
+    dest = forms.CharField(
+        required=True,
+        max_length=255,
+        label=_l("Recipient")
+    )
     # TODO : change chambre field to address
-    chambre = forms.CharField(required=False, max_length=10, label=_l("Address"))
+    chambre = forms.CharField(
+        required=False,
+        max_length=10,
+        label=_l("Address")
+    )
+
 
 # TODO : change Facture to Invoice
 class EditFactureForm(FieldPermissionFormMixin, NewFactureForm):
@@ -313,7 +331,6 @@ class NewFactureSoldeForm(NewFactureForm):
         # TODO : change paiement to payment and baque to bank
         fields = ['paiement', 'banque']
 
-
     def clean(self):
         cleaned_data = super(NewFactureSoldeForm, self).clean()
         # TODO : change paiement to payment
@@ -342,7 +359,7 @@ class RechargeForm(FormRevMixin, Form):
     value = forms.FloatField(
         label=_l("Amount"),
         min_value=0.01,
-        validators = []
+        validators=[]
     )
 
     def __init__(self, *args, **kwargs):
@@ -360,7 +377,8 @@ class RechargeForm(FormRevMixin, Form):
                     )
                 }
             )
-        if value + self.user.solde > OptionalUser.get_cached_value('max_solde'):
+        if value + self.user.solde > \
+                OptionalUser.get_cached_value('max_solde'):
             raise forms.ValidationError(
                 _("Requested amount is too high. Your balance can't exceed \
                 %(max_online_balance)s €.") % {
diff --git a/cotisations/models.py b/cotisations/models.py
index 082847e7..c7b940d6 100644
--- a/cotisations/models.py
+++ b/cotisations/models.py
@@ -54,7 +54,7 @@ class Facture(RevMixin, AclMixin, FieldPermissionModelMixin, models.Model):
     """
     The model for an invoice. It reprensents the fact that a user paid for
     something (it can be multiple article paid at once).
-    
+
     An invoice is linked to :
         * one or more purchases (one for each article sold that time)
         * a user (the one who bought those articles)
@@ -105,11 +105,16 @@ class Facture(RevMixin, AclMixin, FieldPermissionModelMixin, models.Model):
         abstract = False
         permissions = (
             # TODO : change facture to invoice
-            ('change_facture_control', _l("Can change the \"controlled\" state")),
-            # TODO : seems more likely to be call create_facture_pdf or create_invoice_pdf
-            ('change_facture_pdf', _l("Can create a custom PDF invoice")),
-            ('view_facture', _l("Can see an invoice's details")),
-            ('change_all_facture', _l("Can edit all the previous invoices")),
+            ('change_facture_control',
+                _l("Can change the \"controlled\" state")),
+            # TODO : seems more likely to be call create_facture_pdf
+            # or create_invoice_pdf
+            ('change_facture_pdf',
+                _l("Can create a custom PDF invoice")),
+            ('view_facture',
+                _l("Can see an invoice's details")),
+            ('change_all_facture',
+                _l("Can edit all the previous invoices")),
         )
         verbose_name = _l("Invoice")
         verbose_name_plural = _l("Invoices")
@@ -159,11 +164,14 @@ class Facture(RevMixin, AclMixin, FieldPermissionModelMixin, models.Model):
     def can_edit(self, user_request, *args, **kwargs):
         if not user_request.has_perm('cotisations.change_facture'):
             return False, _("You don't have the right to edit an invoice.")
-        elif not user_request.has_perm('cotisations.change_all_facture') and not self.user.can_edit(user_request, *args, **kwargs)[0]:
-            return False, _("You don't have the right to edit this user's invoices.")
-        elif not user_request.has_perm('cotisations.change_all_facture') and\
-            (self.control or not self.valid):
-            return False, _("You don't have the right to edit an invoice already controlled or invalidated.")
+        elif not user_request.has_perm('cotisations.change_all_facture') and \
+                not self.user.can_edit(user_request, *args, **kwargs)[0]:
+            return False, _("You don't have the right to edit this user's "
+                            "invoices.")
+        elif not user_request.has_perm('cotisations.change_all_facture') and \
+                (self.control or not self.valid):
+            return False, _("You don't have the right to edit an invoice "
+                            "already controlled or invalidated.")
         else:
             return True, None
 
@@ -171,16 +179,19 @@ class Facture(RevMixin, AclMixin, FieldPermissionModelMixin, models.Model):
         if not user_request.has_perm('cotisations.delete_facture'):
             return False, _("You don't have the right to delete an invoice.")
         if not self.user.can_edit(user_request, *args, **kwargs)[0]:
-            return False, _("You don't have the right to delete this user's invoices.")
+            return False, _("You don't have the right to delete this user's "
+                            "invoices.")
         if self.control or not self.valid:
-            return False, _("You don't have the right to delete an invoice already controlled or invalidated.")
+            return False, _("You don't have the right to delete an invoice "
+                            "already controlled or invalidated.")
         else:
             return True, None
 
     def can_view(self, user_request, *args, **kwargs):
-        if not user_request.has_perm('cotisations.view_facture') and\
-            self.user != user_request:
-            return False, _("You don't have the right to see someone else's invoices history.")
+        if not user_request.has_perm('cotisations.view_facture') and \
+                self.user != user_request:
+            return False, _("You don't have the right to see someone else's "
+                            "invoices history.")
         elif not self.valid:
             return False, _("The invoice has been invalidated.")
         else:
@@ -188,16 +199,22 @@ class Facture(RevMixin, AclMixin, FieldPermissionModelMixin, models.Model):
 
     @staticmethod
     def can_change_control(user_request, *args, **kwargs):
-        return user_request.has_perm('cotisations.change_facture_control'), _("You don't have the right to edit the \"controlled\" state.")
+        return (
+            user_request.has_perm('cotisations.change_facture_control'),
+            _("You don't have the right to edit the \"controlled\" state.")
+        )
 
     @staticmethod
     def can_change_pdf(user_request, *args, **kwargs):
-        return user_request.has_perm('cotisations.change_facture_pdf'), _("You don't have the right to edit an invoice.")
+        return (
+            user_request.has_perm('cotisations.change_facture_pdf'),
+            _("You don't have the right to edit an invoice.")
+        )
 
     def __init__(self, *args, **kwargs):
         super(Facture, self).__init__(*args, **kwargs)
         self.field_permissions = {
-            'control' : self.can_change_control,
+            'control': self.can_change_control,
         }
 
     def __str__(self):
@@ -228,7 +245,7 @@ class Vente(RevMixin, AclMixin, models.Model):
     """
     The model defining a purchase. It consist of one type of article being
     sold. In particular there may be multiple purchases in a single invoice.
-    
+
     It's reprensentated by:
         * an amount (the number of items sold)
         * an invoice (whose the purchase is part of)
@@ -289,7 +306,6 @@ class Vente(RevMixin, AclMixin, models.Model):
         verbose_name = _l("Purchase")
         verbose_name_plural = _l("Purchases")
 
-
     # TODO : change prix_total to total_price
     def prix_total(self):
         """
@@ -323,11 +339,13 @@ class Vente(RevMixin, AclMixin, models.Model):
                         facture__in=Facture.objects.filter(
                             user=self.facture.user
                         ).exclude(valid=False))
-                    ).filter(Q(type_cotisation='All') | Q(type_cotisation=self.type_cotisation)
+                    ).filter(
+                        Q(type_cotisation='All') |
+                        Q(type_cotisation=self.type_cotisation)
                     ).filter(
                         date_start__lt=date_start
                     ).aggregate(Max('date_end'))['date_end__max']
-            elif self.type_cotisation=="Adhesion":
+            elif self.type_cotisation == "Adhesion":
                 end_cotisation = self.facture.user.end_adhesion()
             else:
                 end_cotisation = self.facture.user.end_connexion()
@@ -357,11 +375,15 @@ class Vente(RevMixin, AclMixin, models.Model):
     def can_edit(self, user_request, *args, **kwargs):
         if not user_request.has_perm('cotisations.change_vente'):
             return False, _("You don't have the right to edit the purchases.")
-        elif not user_request.has_perm('cotisations.change_all_facture') and not self.facture.user.can_edit(user_request, *args, **kwargs)[0]:
-            return False, _("You don't have the right to edit this user's purchases.")
-        elif not user_request.has_perm('cotisations.change_all_vente') and\
-            (self.facture.control or not self.facture.valid):
-            return False, _("You don't have the right to edit a purchase already controlled or invalidated.")
+        elif not user_request.has_perm('cotisations.change_all_facture') and \
+                not self.facture.user.can_edit(
+                    user_request, *args, **kwargs)[0]:
+            return False, _("You don't have the right to edit this user's "
+                            "purchases.")
+        elif not user_request.has_perm('cotisations.change_all_vente') and \
+                (self.facture.control or not self.facture.valid):
+            return False, _("You don't have the right to edit a purchase "
+                            "already controlled or invalidated.")
         else:
             return True, None
 
@@ -369,16 +391,19 @@ class Vente(RevMixin, AclMixin, models.Model):
         if not user_request.has_perm('cotisations.delete_vente'):
             return False, _("You don't have the right to delete a purchase.")
         if not self.facture.user.can_edit(user_request, *args, **kwargs)[0]:
-            return False, _("You don't have the right to delete this user's purchases.")
+            return False, _("You don't have the right to delete this user's "
+                            "purchases.")
         if self.facture.control or not self.facture.valid:
-            return False, _("You don't have the right to delete a purchase already controlled or invalidated.")
+            return False, _("You don't have the right to delete a purchase "
+                            "already controlled or invalidated.")
         else:
             return True, None
 
     def can_view(self, user_request, *args, **kwargs):
-        if not user_request.has_perm('cotisations.view_vente') and\
-            self.facture.user != user_request:
-            return False, _("You don't have the right to see someone else's purchase history.")
+        if not user_request.has_perm('cotisations.view_vente') and \
+                self.facture.user != user_request:
+            return False, _("You don't have the right to see someone "
+                            "else's purchase history.")
         else:
             return True, None
 
@@ -418,12 +443,14 @@ def vente_post_delete(sender, **kwargs):
 
 class Article(RevMixin, AclMixin, models.Model):
     """
-    The definition of an article model. It represents an type of object that can be sold to the user.
-    
+    The definition of an article model. It represents a type of object
+    that can be sold to the user.
+
     It's represented by:
         * a name
         * a price
-        * a cotisation type (indicating if this article reprensents a cotisation or not)
+        * a cotisation type (indicating if this article reprensents a
+            cotisation or not)
         * a duration (if it is a cotisation)
         * a type of user (indicating what kind of user can buy this article)
     """
@@ -513,8 +540,8 @@ class Banque(RevMixin, AclMixin, models.Model):
         permissions = (
             ('view_banque', _l("Can see a bank's details")),
         )
-        verbose_name=_l("Bank")
-        verbose_name_plural=_l("Banks")
+        verbose_name = _l("Bank")
+        verbose_name_plural = _l("Banks")
 
     def __str__(self):
         return self.name
@@ -530,7 +557,7 @@ class Paiement(RevMixin, AclMixin, models.Model):
         * a type (used for the type 'cheque' which implies the use of a bank
             and an account number in related models)
     """
-    
+
     PAYMENT_TYPES = (
         (0, _l("Standard")),
         (1, _l("Cheque")),
@@ -622,24 +649,29 @@ class Cotisation(RevMixin, AclMixin, models.Model):
     def can_edit(self, user_request, *args, **kwargs):
         if not user_request.has_perm('cotisations.change_cotisation'):
             return False, _("You don't have the right to edit a cotisation.")
-        elif not user_request.has_perm('cotisations.change_all_cotisation') and\
-            (self.vente.facture.control or not self.vente.facture.valid):
-            return False, _("You don't have the right to edit a cotisation already controlled or invalidated.")
+        elif not user_request.has_perm('cotisations.change_all_cotisation') \
+                and (self.vente.facture.control or
+                     not self.vente.facture.valid):
+            return False, _("You don't have the right to edit a cotisation "
+                            "already controlled or invalidated.")
         else:
             return True, None
 
     def can_delete(self, user_request, *args, **kwargs):
         if not user_request.has_perm('cotisations.delete_cotisation'):
-            return False, _("You don't have the right to delete a cotisation.")
+            return False, _("You don't have the right to delete a "
+                            "cotisation.")
         if self.vente.facture.control or not self.vente.facture.valid:
-            return False, _("You don't have the right to delete a cotisation already controlled or invalidated.")
+            return False, _("You don't have the right to delete a cotisation "
+                            "already controlled or invalidated.")
         else:
             return True, None
 
     def can_view(self, user_request, *args, **kwargs):
         if not user_request.has_perm('cotisations.view_cotisation') and\
-            self.vente.facture.user != user_request:
-            return False, _("You don't have the right to see someone else's cotisation history.")
+                self.vente.facture.user != user_request:
+            return False, _("You don't have the right to see someone else's "
+                            "cotisation history.")
         else:
             return True, None
 
diff --git a/cotisations/payment.py b/cotisations/payment.py
index 652037fb..8efdd344 100644
--- a/cotisations/payment.py
+++ b/cotisations/payment.py
@@ -17,6 +17,7 @@ from preferences.models import AssoOption
 from .models import Facture
 from .payment_utils.comnpay import Payment as ComnpayPayment
 
+
 @csrf_exempt
 @login_required
 def accept_payment(request, factureid):
@@ -30,7 +31,10 @@ def accept_payment(request, factureid):
             'amount': facture.prix()
         }
     )
-    return redirect(reverse('users:profil', kwargs={'userid':request.user.id}))
+    return redirect(reverse(
+        'users:profil',
+        kwargs={'userid': request.user.id}
+    ))
 
 
 @csrf_exempt
@@ -43,7 +47,11 @@ def refuse_payment(request):
         request,
         _("The payment has been refused.")
     )
-    return redirect(reverse('users:profil', kwargs={'userid':request.user.id}))
+    return redirect(reverse(
+        'users:profil',
+        kwargs={'userid': request.user.id}
+    ))
+
 
 @csrf_exempt
 def ipn(request):
@@ -105,7 +113,7 @@ def comnpay(facture, request):
         str(AssoOption.get_cached_value('payment_pass')),
         'https://' + host + reverse(
             'cotisations:accept_payment',
-            kwargs={'factureid':facture.id}
+            kwargs={'factureid': facture.id}
         ),
         'https://' + host + reverse('cotisations:refuse_payment'),
         'https://' + host + reverse('cotisations:ipn'),
@@ -113,20 +121,20 @@ def comnpay(facture, request):
         "D"
     )
     r = {
-        'action' : 'https://secure.homologation.comnpay.com',
-        'method' : 'POST',
-        'content' : p.buildSecretHTML(
+        'action': 'https://secure.homologation.comnpay.com',
+        'method': 'POST',
+        'content': p.buildSecretHTML(
             "Rechargement du solde",
             facture.prix(),
             idTransaction=str(facture.id)
         ),
-        'amount' : facture.prix,
+        'amount': facture.prix,
     }
     return r
 
 
 # The payment systems supported by re2o
 PAYMENT_SYSTEM = {
-    'COMNPAY' : comnpay,
-    'NONE' : None
+    'COMNPAY': comnpay,
+    'NONE': None
 }
diff --git a/cotisations/payment_utils/comnpay.py b/cotisations/payment_utils/comnpay.py
index 6c1701d3..dcf7e22a 100644
--- a/cotisations/payment_utils/comnpay.py
+++ b/cotisations/payment_utils/comnpay.py
@@ -5,6 +5,7 @@ import hashlib
 from collections import OrderedDict
 from itertools import chain
 
+
 class Payment():
 
     vad_number = ""
@@ -15,7 +16,8 @@ class Payment():
     source = ""
     typeTr = "D"
 
-    def __init__(self, vad_number = "", secret_key = "", urlRetourOK = "", urlRetourNOK = "", urlIPN = "", source="", typeTr="D"):
+    def __init__(self, vad_number="", secret_key="", urlRetourOK="",
+                 urlRetourNOK="", urlIPN="", source="", typeTr="D"):
         self.vad_number = vad_number
         self.secret_key = secret_key
         self.urlRetourOK = urlRetourOK
@@ -24,36 +26,45 @@ class Payment():
         self.source = source
         self.typeTr = typeTr
 
-    def buildSecretHTML(self, produit="Produit", montant="0.00", idTransaction=""):
+    def buildSecretHTML(self, produit="Produit", montant="0.00",
+                        idTransaction=""):
         if idTransaction == "":
-            self.idTransaction = str(time.time())+self.vad_number+str(randrange(999))
+            self.idTransaction = str(time.time())
+            self.idTransaction += self.vad_number
+            self.idTransaction += str(randrange(999))
         else:
             self.idTransaction = idTransaction
 
-        array_tpe   = OrderedDict(
-                montant= str(montant),
-                idTPE= self.vad_number,
-                idTransaction= self.idTransaction,
-                devise= "EUR",
-                lang= 'fr',
-                nom_produit= produit,
-                source= self.source,
-                urlRetourOK= self.urlRetourOK,
-                urlRetourNOK= self.urlRetourNOK,
-                typeTr= str(self.typeTr)
+        array_tpe = OrderedDict(
+                montant=str(montant),
+                idTPE=self.vad_number,
+                idTransaction=self.idTransaction,
+                devise="EUR",
+                lang='fr',
+                nom_produit=produit,
+                source=self.source,
+                urlRetourOK=self.urlRetourOK,
+                urlRetourNOK=self.urlRetourNOK,
+                typeTr=str(self.typeTr)
         )
 
-        if self.urlIPN!="":
+        if self.urlIPN != "":
             array_tpe['urlIPN'] = self.urlIPN
 
-        array_tpe['key'] = self.secret_key;
-        strWithKey = base64.b64encode(bytes('|'.join(array_tpe.values()), 'utf-8'))
+        array_tpe['key'] = self.secret_key
+        strWithKey = base64.b64encode(bytes(
+            '|'.join(array_tpe.values()),
+            'utf-8'
+        ))
         del array_tpe["key"]
         array_tpe['sec'] = hashlib.sha512(strWithKey).hexdigest()
 
         ret = ""
         for key in array_tpe:
-            ret += '<input type="hidden" name="'+key+'" value="'+array_tpe[key]+'"/>'
+            ret += '<input type="hidden" name="{k}" value="{v}"/>'.format(
+                'k'=key,
+                'v'=array_type[key]
+            )
 
         return ret
 
@@ -61,8 +72,10 @@ class Payment():
         if "sec" in values:
             sec = values['sec']
             del values["sec"]
-            strWithKey = hashlib.sha512(base64.b64encode(bytes('|'.join(values.values()) +"|"+secret_key, 'utf-8'))).hexdigest()
+            strWithKey = hashlib.sha512(base64.b64encode(bytes(
+                '|'.join(values.values()) + "|" + secret_key,
+                'utf-8'
+            ))).hexdigest()
             return strWithKey.upper() == sec.upper()
         else:
             return False
-
diff --git a/cotisations/tex.py b/cotisations/tex.py
index fb50d05b..95f12b93 100644
--- a/cotisations/tex.py
+++ b/cotisations/tex.py
@@ -46,7 +46,7 @@ def render_invoice(request, ctx={}):
     date, the user, the articles, the prices, ...
     """
     filename = '_'.join([
-        'invoice', 
+        'invoice',
         slugify(ctx['asso_name']),
         slugify(ctx['recipient_name']),
         str(ctx['DATE'].year),
@@ -54,9 +54,12 @@ def render_invoice(request, ctx={}):
         str(ctx['DATE'].day),
     ])
     r = render_tex(request, 'cotisations/factures.tex', ctx)
-    r['Content-Disposition'] = ''.join(['attachment; filename="',filename,'.pdf"']) 
+    r['Content-Disposition'] = 'attachment; filename="{name}.pdf"'.format(
+        name=filename
+    )
     return r
 
+
 def render_tex(request, template, ctx={}):
     """
     Creates a PDF from a LaTex templates using pdflatex.
@@ -66,13 +69,13 @@ def render_tex(request, template, ctx={}):
     context = Context(ctx)
     template = get_template(template)
     rendered_tpl = template.render(context).encode('utf-8')
-    
+
     with tempfile.TemporaryDirectory() as tempdir:
         for i in range(2):
             process = Popen(
                 ['pdflatex', '-output-directory', tempdir],
-                stdin = PIPE,
-                stdout = PIPE,
+                stdin=PIPE,
+                stdout=PIPE,
             )
             process.communicate(rendered_tpl)
         with open(os.path.join(tempdir, 'texput.pdf'), 'rb') as f:
diff --git a/cotisations/urls.py b/cotisations/urls.py
index 0040e48c..05b1a7a3 100644
--- a/cotisations/urls.py
+++ b/cotisations/urls.py
@@ -101,12 +101,11 @@ urlpatterns = [
         views.index_paiement,
         name='index-paiement'
         ),
-    url(
-        r'history/(?P<object_name>\w+)/(?P<object_id>[0-9]+)$',
+    url(r'history/(?P<object_name>\w+)/(?P<object_id>[0-9]+)$',
         re2o.views.history,
         name='history',
-        kwargs={'application':'cotisations'},
-    ),
+        kwargs={'application': 'cotisations'},
+        ),
     url(r'^control/$',
         views.control,
         name='control'
@@ -122,14 +121,14 @@ urlpatterns = [
     url(r'^payment/accept/(?P<factureid>[0-9]+)$',
         payment.accept_payment,
         name='accept_payment'
-       ),
+        ),
     url(r'^payment/refuse/$',
         payment.refuse_payment,
         name='refuse_payment'
-       ),
+        ),
     url(r'^payment/ipn/$',
         payment.ipn,
         name='ipn'
-       ),
+        ),
     url(r'^$', views.index, name='index'),
 ]
diff --git a/cotisations/views.py b/cotisations/views.py
index 631713e8..c8c68c19 100644
--- a/cotisations/views.py
+++ b/cotisations/views.py
@@ -77,7 +77,6 @@ from . import payment as online_payment
 from .tex import render_invoice
 
 
-
 @login_required
 @can_create(Facture)
 @can_edit(User)
@@ -102,9 +101,13 @@ def new_facture(request, user, userid):
     # Building the invocie form and the article formset
     invoice_form = NewFactureForm(request.POST or None, instance=invoice)
     if request.user.is_class_club:
-        article_formset = formset_factory(SelectClubArticleForm)(request.POST or None)
+        article_formset = formset_factory(SelectClubArticleForm)(
+            request.POST or None
+        )
     else:
-        article_formset = formset_factory(SelectUserArticleForm)(request.POST or None)
+        article_formset = formset_factory(SelectUserArticleForm)(
+            request.POST or None
+        )
 
     if invoice_form.is_valid() and article_formset.is_valid():
         new_invoice_instance = invoice_form.save(commit=False)
@@ -118,15 +121,18 @@ def new_facture(request, user, userid):
             # the authorized minimum (negative_balance)
             if user_balance:
                 # TODO : change Paiement to Payment
-                if new_invoice_instance.paiement == Paiement.objects.get_or_create(
-                        moyen='solde'
-                )[0]:
+                if new_invoice_instance.paiement == (
+                    Paiement.objects.get_or_create(moyen='solde')[0]
+                ):
                     total_price = 0
                     for art_item in articles:
                         if art_item.cleaned_data:
-                            total_price += art_item.cleaned_data['article']\
-                                    .prix*art_item.cleaned_data['quantity']
-                    if float(user.solde) - float(total_price) < negative_balance:
+                            total_price += (
+                                art_item.cleaned_data['article'].prix *
+                                art_item.cleaned_data['quantity']
+                            )
+                    if (float(user.solde) - float(total_price)
+                            < negative_balance):
                         messages.error(
                             request,
                             _("Your balance is too low for this operation.")
@@ -194,7 +200,7 @@ def new_facture(request, user, userid):
 @can_change(Facture, 'pdf')
 def new_facture_pdf(request):
     """
-    View used to generate a custom PDF invoice. It's mainly used to 
+    View used to generate a custom PDF invoice. It's mainly used to
     get invoices that are not taken into account, for the administrative
     point of view.
     """
@@ -205,9 +211,13 @@ def new_facture_pdf(request):
     # Building the invocie form and the article formset
     invoice_form = NewFactureFormPdf(request.POST or None)
     if request.user.is_class_club:
-        articles_formset = formset_factory(SelectClubArticleForm)(request.POST or None)
+        articles_formset = formset_factory(SelectClubArticleForm)(
+            request.POST or None
+        )
     else:
-        articles_formset = formset_factory(SelectUserArticleForm)(request.POST or None)
+        articles_formset = formset_factory(SelectUserArticleForm)(
+            request.POST or None
+        )
     if invoice_form.is_valid() and articles_formset.is_valid():
         # Get the article list and build an list out of it
         # contiaining (article_name, article_price, quantity, total_price)
@@ -303,7 +313,11 @@ def edit_facture(request, facture, factureid):
     can be set as desired. This is also the view used to invalidate
     an invoice.
     """
-    invoice_form = EditFactureForm(request.POST or None, instance=facture, user=request.user)
+    invoice_form = EditFactureForm(
+        request.POST or None,
+        instance=facture,
+        user=request.user
+    )
     purchases_objects = Vente.objects.filter(facture=facture)
     purchase_form_set = modelformset_factory(
         Vente,
@@ -311,7 +325,10 @@ def edit_facture(request, facture, factureid):
         extra=0,
         max_num=len(purchases_objects)
         )
-    purchase_form = purchase_form_set(request.POST or None, queryset=purchases_objects)
+    purchase_form = purchase_form_set(
+        request.POST or None,
+        queryset=purchases_objects
+    )
     if invoice_form.is_valid() and purchase_form.is_valid():
         if invoice_form.changed_data:
             invoice_form.save()
@@ -385,7 +402,7 @@ def credit_solde(request, user, userid):
 def add_article(request):
     """
     View used to add an article.
-    
+
     .. note:: If a purchase has already been sold, the price are calculated
         once and for all. That means even if the price of an article is edited
         later, it won't change the invoice. That is really important to keep
@@ -613,7 +630,8 @@ def control(request):
     View used to control the invoices all at once.
     """
     pagination_number = GeneralOption.get_cached_value('pagination_number')
-    invoice_list = Facture.objects.select_related('user').select_related('paiement')
+    invoice_list = (Facture.objects.select_related('user').
+                    select_related('paiement'))
     invoice_list = SortTable.sort(
         invoice_list,
         request.GET.get('col'),
@@ -725,9 +743,13 @@ def new_facture_solde(request, userid):
         Q(type_user='All') | Q(type_user=request.user.class_name)
     )
     if request.user.is_class_club:
-        article_formset = formset_factory(SelectClubArticleForm)(request.POST or None)
+        article_formset = formset_factory(SelectClubArticleForm)(
+            request.POST or None
+        )
     else:
-        article_formset = formset_factory(SelectUserArticleForm)(request.POST or None)
+        article_formset = formset_factory(SelectUserArticleForm)(
+            request.POST or None
+        )
 
     if article_formset.is_valid():
         articles = article_formset
@@ -826,7 +848,9 @@ def recharge(request):
     refill_form = RechargeForm(request.POST or None, user=request.user)
     if refill_form.is_valid():
         invoice = Facture(user=request.user)
-        payment, _created = Paiement.objects.get_or_create(moyen='Rechargement en ligne')
+        payment, _created = Paiement.objects.get_or_create(
+            moyen='Rechargement en ligne'
+        )
         invoice.paiement = payment
         invoice.valid = False
         invoice.save()
@@ -837,7 +861,9 @@ def recharge(request):
             number=1
         )
         purchase.save()
-        content = online_payment.PAYMENT_SYSTEM[AssoOption.get_cached_value('payment')](invoice, request)
+        content = online_payment.PAYMENT_SYSTEM[
+            AssoOption.get_cached_value('payment')
+        ](invoice, request)
         return render(request, 'cotisations/payment.html', content)
     return form({
         'rechargeform': refill_form