De-register an extended property that has been registered with register()

def deregister(cls, attr_name):
        """
        De-register an extended property that has been registered with register()
        """
        try:
            field = cls.get_field_by_fieldname(attr_name)
        except InvalidField:
            raise ValueError("'%s' is not registered" % attr_name)
        if not isinstance(field, ExtendedPropertyField):
            raise ValueError("'%s' is not registered as an ExtendedProperty" % attr_name)
        cls.remove_field(field)