def get_orig_data_from_existing(self, obj):
raise NotImplementedError<EOL>
Return a dictionary of field names and values for a given object.

        The values in the dictionary should be in their "cleaned" state (as
        in, exactly as they were set on the object, without any serialization).

        :param object obj: existing object for which new data is currently
            being cleaned.
        :returns: dict of fields and values that are currently set on the
            object (before the new cleaned data is applied).