Changed datahandler exceptions from functions to classes

lodel/leapi/datahandlers/exceptions.py

@@ -1,6 +1,6 @@
-def LodelDataHandlerException(Exception):
+class LodelDataHandlerException(Exception):
     pass
 
 
-def LodelDataHandlerConsistencyException(LodelDataHandlerException):
+class LodelDataHandlerConsistencyException(LodelDataHandlerException):
     pass