def CheckFlowException(user, sourceServiceRecord, targetServiceRecord):
        ''' returns true if there is a flow exception blocking activities moving from source to destination '''
        forwardException = {"Target": {"Service": targetServiceRecord.Service.ID, "ExternalID": targetServiceRecord.ExternalID}, "Source": {"Service": sourceServiceRecord.Service.ID, "ExternalID": sourceServiceRecord.ExternalID}}
        return "FlowExceptions" in user and forwardException in user["FlowExceptions"]
 returns true if there is a flow exception blocking activities moving from source to destination 
tapiriik/auth/__init__.py