diff --git a/beat/web/common/mixins.py b/beat/web/common/mixins.py
index b02307999649c7e42c11613175add7a01ed94a50..24bfd2b6b398ed9c4a035e95ee4e9d41a8896ba4 100644
--- a/beat/web/common/mixins.py
+++ b/beat/web/common/mixins.py
@@ -25,8 +25,6 @@
 #                                                                             #
 ###############################################################################
 
-from rest_framework import permissions
-from .permissions import IsAuthor
 
 class CommonContextMixin(object):
     """
@@ -34,16 +32,17 @@ class CommonContextMixin(object):
     request user in the serializer context
     optionnaly the request object format
     """
+
     def get_serializer_context(self):
         context = super(CommonContextMixin, self).get_serializer_context()
-        context['user'] = self.request.user
+        context["user"] = self.request.user
 
-        object_format = self.request.GET.get('object_format', None)
+        object_format = self.request.GET.get("object_format", None)
         if object_format is not None:
-            if object_format not in ['json', 'string']:
-                object_format = 'json'
+            if object_format not in ["json", "string"]:
+                object_format = "json"
 
-            context['object_format'] = object_format
+            context["object_format"] = object_format
 
         return context
 
@@ -53,52 +52,27 @@ class SerializerFieldsMixin(object):
     Apply this mixin to any view or viewset to get the
     list of fields to return
     """
+
     def get_serializer_fields(self, request, allow_sharing=False, exclude_fields=[]):
         # Process the query string
         fields = None
         query_params = request.query_params
 
-        if 'fields' in query_params:
-            fields = query_params['fields'].split(',')
+        if "fields" in query_params:
+            fields = query_params["fields"].split(",")
         else:
             fields = self.get_serializer_class().Meta.default_fields
 
-        if 'include_fields' in query_params:
-            include_fields = query_params['include_fields'].split(',')
+        if "include_fields" in query_params:
+            include_fields = query_params["include_fields"].split(",")
             fields.extend(include_fields)
 
-        if not(allow_sharing):
-            exclude_fields = ['sharing'] + exclude_fields
+        if not (allow_sharing):
+            exclude_fields = ["sharing"] + exclude_fields
 
         if request.user.is_anonymous():
-            exclude_fields = ['is_owner'] + exclude_fields
+            exclude_fields = ["is_owner"] + exclude_fields
 
         fields = [field for field in fields if field not in exclude_fields]
 
         return fields
-
-
-class IsAuthorOrReadOnlyMixin(object):
-    """
-    Apply this mixin to any view or viewset. Allows read for
-    all and modification only by author
-    """
-    def get_permissions(self):
-        if self.request.method == 'GET':
-            self.permission_classes = [permissions.AllowAny]
-        else:
-            self.permission_classes = [permissions.IsAuthenticated, IsAuthor]
-        return super(IsAuthorOrReadOnlyMixin, self).get_permissions()
-
-
-class IsAdminOrReadOnlyMixin(object):
-    """
-    Apply this mixin to any view or viewset. Allows read for
-    all and modification only by admin
-    """
-    def get_permissions(self):
-        if self.request.method == 'GET':
-            self.permission_classes = [permissions.AllowAny]
-        else:
-            self.permission_classes = [permissions.IsAuthenticated, permissions.IsAdminUser]
-        return super(IsAdminOrReadOnlyMixin, self).get_permissions()