Fixed #14257 -- removed ManyToManyField.isValidIDList which was completely...

                    break

        return getattr(self, cache_attr)

    def isValidIDList(self, field_data, all_data):

        "Validates that the value is a valid list of foreign keys"

        mod = self.rel.to

        try:

            pks = map(int, field_data.split(','))

        except ValueError:

            # the CommaSeparatedIntegerField validator will catch this error

            return

        objects = mod._default_manager.in_bulk(pks)

        if len(objects) != len(pks):

            badkeys = [k for k in pks if k not in objects]

            raise exceptions.ValidationError(

                ungettext("Please enter valid %(self)s IDs. The value %(value)r is invalid.",

                          "Please enter valid %(self)s IDs. The values %(value)r are invalid.",

                          len(badkeys)) % {

                'self': self.verbose_name,

                'value': len(badkeys) == 1 and badkeys[0] or tuple(badkeys),

            })

    def value_to_string(self, obj):

        data = ''

        if obj: