Check to make sure the teaching object which will be used as a dictionary key is hashable

def _validate_teaching(cls, belief, teaching, *args, **kwargs):
        """
        Check to make sure the teaching object which will be used as a dictionary key is hashable
        """
        if teaching.__hash__ is None:
            raise DictionaryDogmaException(''''The belief '%s' does not have a hashable teaching '%s' ''' % (belief, teaching ))

        return teaching