diff --git a/endpoints/api/permission_models_interface.py b/endpoints/api/permission_models_interface.py
index 40bba3039..1e541d2a5 100644
--- a/endpoints/api/permission_models_interface.py
+++ b/endpoints/api/permission_models_interface.py
@@ -74,38 +74,135 @@ class TeamPermission(namedtuple('TeamPermission', [
 
 @add_metaclass(ABCMeta)
 class PermissionDataInterface(object):
+  """
+  Data interface used by permissions API
+  """
+  
   @abstractmethod
   def get_repo_permissions_by_user(self, namespace_name, repository_name):
-    pass
+    """
+    
+    Args:
+      namespace_name: string
+      repository_name: string
+
+    Returns:
+      list(UserPermission)
+    """
 
   @abstractmethod
   def get_repo_roles(self, username, namespace_name, repository_name):
-    pass
+    """
+    
+    Args:
+      username: string
+      namespace_name: string
+      repository_name: string
+
+    Returns:
+      list(Role) or None
+    """  
   
   @abstractmethod
   def get_repo_permission_for_user(self, username, namespace_name, repository_name):
-    pass
+    """
+    
+    Args:
+      username: string
+      namespace_name: string
+      repository_name: string
+
+    Returns:
+      UserPermission
+    """
   
   @abstractmethod
   def set_repo_permission_for_user(self, username, namespace_name, repository_name, role_name):
-    pass
+    """
+    
+    Args:
+      username: string
+      namespace_name: string
+      repository_name: string
+      role_name: string
+
+    Returns:
+      UserPermission
+      
+    Raises:
+      SaveException
+    """
 
   @abstractmethod
   def delete_repo_permission_for_user(self, username, namespace_name, repository_name):
-    pass
+    """
+    
+    Args:
+      username: string
+      namespace_name: string
+      repository_name: string
+
+    Returns:
+      void
+      
+    Raises:
+      DeleteException
+    """
 
   @abstractmethod
   def get_repo_permissions_by_team(self, namespace_name, repository_name):
-    pass
+    """
+    
+    Args:
+      namespace_name: string
+      repository_name: string
+
+    Returns:
+      list(TeamPermission)
+    """
 
   @abstractmethod
   def get_repo_role_for_team(self, team_name, namespace_name, repository_name):
-    pass
+    """
+    
+    Args:
+      team_name: string
+      namespace_name: string
+      repository_name: string
+
+    Returns:
+      Role
+    """
 
   @abstractmethod
   def set_repo_permission_for_team(self, team_name, namespace_name, repository_name, permission):
-    pass
+    """
+    
+    Args:
+      team_name: string
+      namespace_name: string
+      repository_name: string
+      permission: string
+
+    Returns:
+      TeamPermission
+      
+    Raises:
+      SaveException
+    """
 
   @abstractmethod
   def delete_repo_permission_for_team(self, team_name, namespace_name, repository_name):
-    pass
\ No newline at end of file
+    """
+    
+    Args:
+      team_name: string
+      namespace_name: string
+      repository_name: string
+
+    Returns:
+      TeamPermission
+      
+    Raises:
+      DeleteException
+    """
\ No newline at end of file
diff --git a/endpoints/api/permission_models_pre_oci.py b/endpoints/api/permission_models_pre_oci.py
index 07cee95ef..1f19cad10 100644
--- a/endpoints/api/permission_models_pre_oci.py
+++ b/endpoints/api/permission_models_pre_oci.py
@@ -30,10 +30,8 @@ class PreOCIModel(PermissionDataInterface):
 
       return user.robot or user.username in org_members
       
-      
     return [self._user_permission(perm, org is not None, is_org_member(perm.user)) for perm in repo_perms]
             
-
   def get_repo_roles(self, username, namespace_name, repository_name):
     user = model.user.get_user(username)
     if not user:
@@ -98,7 +96,6 @@ class PreOCIModel(PermissionDataInterface):
     except model.DataModelException as ex:
       raise DeleteException(ex)
     
-    
   def _role(self, permission_obj):
     return Role(role_name=permission_obj.role.name)
   
@@ -115,4 +112,4 @@ class PreOCIModel(PermissionDataInterface):
                           team_name=permission_obj.team.name,
                           avatar=avatar.get_data_for_team(permission_obj.team))
 
-pre_oci_model = PreOCIModel()
\ No newline at end of file
+pre_oci_model = PreOCIModel()