--- a/cubicweb/web/_exceptions.py	Thu May 16 02:39:40 2019 +0200
+++ b/cubicweb/web/_exceptions.py	Thu May 16 02:39:41 2019 +0200
@@ -30,12 +30,14 @@
     def __init__(self, response):
         self.response = response
 
+
 class InvalidSession(CubicWebException):
     """raised when a session id is found but associated session is not found or
     invalid"""
 
 # Publish related exception
 
+
 class PublishException(CubicWebException):
     """base class for publishing related exception"""
 
@@ -43,6 +45,7 @@
         self.status = kwargs.pop('status', http_client.OK)
         super(PublishException, self).__init__(*args, **kwargs)
 
+
 class LogOut(PublishException):
     """raised to ask for deauthentication of a logged in user"""
 
@@ -50,6 +53,7 @@
         super(LogOut, self).__init__()
         self.url = url
 
+
 class Redirect(PublishException):
     """raised to redirect the http request"""
 
@@ -57,6 +61,7 @@
         super(Redirect, self).__init__(status=status)
         self.location = location
 
+
 class StatusResponse(PublishException):
 
     def __init__(self, status, content=''):
@@ -68,6 +73,7 @@
 
 # Publish related error
 
+
 class RequestError(PublishException):
     """raised when a request can't be served because of a bad input"""
 
@@ -83,6 +89,7 @@
         kwargs.setdefault('status', http_client.BAD_REQUEST)
         super(NothingToEdit, self).__init__(*args, **kwargs)
 
+
 class ProcessFormError(RequestError):
     """raised when posted data can't be processed by the corresponding field
     """
@@ -91,6 +98,7 @@
         kwargs.setdefault('status', http_client.BAD_REQUEST)
         super(ProcessFormError, self).__init__(*args, **kwargs)
 
+
 class NotFound(RequestError):
     """raised when something was not found. In most case,
        a 404 error should be returned"""
@@ -99,6 +107,7 @@
         kwargs.setdefault('status', http_client.NOT_FOUND)
         super(NotFound, self).__init__(*args, **kwargs)
 
+
 class RemoteCallFailed(RequestError):
     """raised when a json remote call fails
     """