[Exceptions] pep8+pylint on exceptions.py

EditorialModel/exceptions.py

 # -*- coding: utf-8 -*-
 
+
 ## @brief An exception class to tell that a component don't exist
 class EmComponentNotExistError(Exception):
     pass
 
+
 ## @brief Raised on uniq constraint error at creation
 # This exception class is dedicated to be raised when create() method is called
 # if an EmComponent with this name but different parameters allready exist
 class EmComponentExistError(Exception):
     pass
 
+
 ## @brief An exception class to tell that no ranking exist yet for the group of the object
 class EmComponentRankingNotExistError(Exception):
     pass
 
+
 ## @brief An exception class to return a failure reason for EmComponent.check() method
 class EmComponentCheckError(Exception):
     pass
 
+
 class MigrationHandlerChangeError(Exception):
     pass