diff --git a/mellon/adapters.py b/mellon/adapters.py
index 8c869a3..ce71629 100644
--- a/mellon/adapters.py
+++ b/mellon/adapters.py
@@ -1,3 +1,18 @@
+# django-mellon - SAML2 authentication for Django
+# Copyright (C) 2014-2019 Entr'ouvert
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
 import logging
 import uuid
 from xml.etree import ElementTree as ET
@@ -76,7 +91,7 @@ class DefaultAdapter(object):
                     self.logger.error(u'METADATA of %d-th idp has no EntityDescriptor root tag', i)
                     continue
 
-                if not 'entityID' in doc.attrib:
+                if 'entityID' not in doc.attrib:
                     self.logger.error(
                         u'METADATA of %d-th idp has no entityID attribute on its root tag', i)
                     continue
@@ -105,7 +120,7 @@ class DefaultAdapter(object):
         except (AttributeError, KeyError, IndexError) as e:
             self.logger.error(
                 u'invalid reference in username template %r: %s', username_template, e)
-        except Exception as e:
+        except Exception:
             self.logger.exception(u'unknown error when formatting username')
         else:
             return username
diff --git a/mellon/middleware.py b/mellon/middleware.py
index a0b814a..8e79218 100644
--- a/mellon/middleware.py
+++ b/mellon/middleware.py
@@ -1,3 +1,18 @@
+# django-mellon - SAML2 authentication for Django
+# Copyright (C) 2014-2019 Entr'ouvert
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
 from django.utils.http import urlencode
 from django.http import HttpResponseRedirect
 from django.core.urlresolvers import reverse
diff --git a/mellon/models.py b/mellon/models.py
index 9368a1d..62cf842 100644
--- a/mellon/models.py
+++ b/mellon/models.py
@@ -1,3 +1,18 @@
+# django-mellon - SAML2 authentication for Django
+# Copyright (C) 2014-2019 Entr'ouvert
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
 from django.db import models
 from django.utils.translation import ugettext_lazy as _
 from django.conf import settings
diff --git a/mellon/sessions_backends/cached_db.py b/mellon/sessions_backends/cached_db.py
index 7e3aed0..b30a977 100644
--- a/mellon/sessions_backends/cached_db.py
+++ b/mellon/sessions_backends/cached_db.py
@@ -1,3 +1,18 @@
+# django-mellon - SAML2 authentication for Django
+# Copyright (C) 2014-2019 Entr'ouvert
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
 from django.contrib.sessions.backends.db import SessionStore
 
 from . import db
diff --git a/mellon/sessions_backends/db.py b/mellon/sessions_backends/db.py
index 9c89e86..a45eadf 100644
--- a/mellon/sessions_backends/db.py
+++ b/mellon/sessions_backends/db.py
@@ -1,3 +1,18 @@
+# django-mellon - SAML2 authentication for Django
+# Copyright (C) 2014-2019 Entr'ouvert
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
 from django.contrib.sessions.backends.db import SessionStore
 
 from mellon import utils
diff --git a/mellon/utils.py b/mellon/utils.py
index 1c48f1a..d50153b 100644
--- a/mellon/utils.py
+++ b/mellon/utils.py
@@ -1,3 +1,18 @@
+# django-mellon - SAML2 authentication for Django
+# Copyright (C) 2014-2019 Entr'ouvert
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
 import logging
 import datetime
 import importlib
@@ -29,16 +44,16 @@ def create_metadata(request):
         public_keys.append(public_key)
     name_id_formats = app_settings.NAME_ID_FORMATS
     return render_to_string('mellon/metadata.xml', {
-            'entity_id': request.build_absolute_uri(entity_id),
-            'login_url': request.build_absolute_uri(login_url),
-            'logout_url': request.build_absolute_uri(logout_url),
-            'public_keys': public_keys,
-            'name_id_formats': name_id_formats,
-            'default_assertion_consumer_binding': app_settings.DEFAULT_ASSERTION_CONSUMER_BINDING,
-            'organization': app_settings.ORGANIZATION,
-            'contact_persons': app_settings.CONTACT_PERSONS,
-            'discovery_endpoint_url': request.build_absolute_uri(reverse('mellon_login')),
-        })
+        'entity_id': request.build_absolute_uri(entity_id),
+        'login_url': request.build_absolute_uri(login_url),
+        'logout_url': request.build_absolute_uri(logout_url),
+        'public_keys': public_keys,
+        'name_id_formats': name_id_formats,
+        'default_assertion_consumer_binding': app_settings.DEFAULT_ASSERTION_CONSUMER_BINDING,
+        'organization': app_settings.ORGANIZATION,
+        'contact_persons': app_settings.CONTACT_PERSONS,
+        'discovery_endpoint_url': request.build_absolute_uri(reverse('mellon_login')),
+    })
 
 
 def create_server(request):
@@ -130,7 +145,7 @@ def iso8601_to_datetime(date_string, default=None):
        This function ignores the sub-second resolution'''
     try:
         dt = isodate.parse_datetime(date_string)
-    except:
+    except Exception:
         return default
     if is_aware(dt):
         if not settings.USE_TZ:
@@ -209,7 +224,7 @@ def create_logout(request):
 
 
 def is_nonnull(s):
-    return not '\x00' in s
+    return '\x00' not in s
 
 
 def same_origin(url1, url2):
@@ -244,6 +259,7 @@ def get_status_codes_and_message(profile):
         message = lasso_decode(status.statusMessage)
     return status_codes, message
 
+
 def login(request, user):
     for adapter in get_adapters():
         if hasattr(adapter, 'auth_login'):
diff --git a/mellon/views.py b/mellon/views.py
index 5a39adf..9a685e9 100644
--- a/mellon/views.py
+++ b/mellon/views.py
@@ -1,3 +1,18 @@
+# django-mellon - SAML2 authentication for Django
+# Copyright (C) 2014-2019 Entr'ouvert
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
 import logging
 import requests
 import lasso
diff --git a/tests/conftest.py b/tests/conftest.py
index bfa8788..9458b5f 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -1,3 +1,18 @@
+# django-mellon - SAML2 authentication for Django
+# Copyright (C) 2014-2019 Entr'ouvert
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
 import logging
 import pytest
 import django_webtest
diff --git a/tests/test_default_adapter.py b/tests/test_default_adapter.py
index 43c9064..7efe2f0 100644
--- a/tests/test_default_adapter.py
+++ b/tests/test_default_adapter.py
@@ -1,3 +1,18 @@
+# django-mellon - SAML2 authentication for Django
+# Copyright (C) 2014-2019 Entr'ouvert
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
 import pytest
 import re
 import lasso
diff --git a/tests/test_sso_slo.py b/tests/test_sso_slo.py
index 42ab8ef..fdd2087 100644
--- a/tests/test_sso_slo.py
+++ b/tests/test_sso_slo.py
@@ -1,3 +1,18 @@
+# django-mellon - SAML2 authentication for Django
+# Copyright (C) 2014-2019 Entr'ouvert
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
 import re
 import base64
 import zlib
diff --git a/tests/test_utils.py b/tests/test_utils.py
index 8c4cf9c..b0f0b2b 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -1,3 +1,18 @@
+# django-mellon - SAML2 authentication for Django
+# Copyright (C) 2014-2019 Entr'ouvert
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
 import re
 import datetime
 
diff --git a/tests/test_views.py b/tests/test_views.py
index 014af86..6babf67 100644
--- a/tests/test_views.py
+++ b/tests/test_views.py
@@ -1,3 +1,18 @@
+# django-mellon - SAML2 authentication for Django
+# Copyright (C) 2014-2019 Entr'ouvert
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
 import pytest
 import mock
 import lasso
diff --git a/tests/urls_tests.py b/tests/urls_tests.py
index d95e2c0..52500a4 100644
--- a/tests/urls_tests.py
+++ b/tests/urls_tests.py
@@ -1,3 +1,18 @@
+# django-mellon - SAML2 authentication for Django
+# Copyright (C) 2014-2019 Entr'ouvert
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
 import django
 
 from django.conf.urls import url, include
diff --git a/tests/utils.py b/tests/utils.py
index 388e6c0..d4b7883 100644
--- a/tests/utils.py
+++ b/tests/utils.py
@@ -1,3 +1,18 @@
+# django-mellon - SAML2 authentication for Django
+# Copyright (C) 2014-2019 Entr'ouvert
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
 from httmock import all_requests, response
 
 
diff --git a/tests/xml_utils.py b/tests/xml_utils.py
index 670c6b4..a154f15 100644
--- a/tests/xml_utils.py
+++ b/tests/xml_utils.py
@@ -1,3 +1,18 @@
+# django-mellon - SAML2 authentication for Django
+# Copyright (C) 2014-2019 Entr'ouvert
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
 from lxml import etree as ET