'Check that list_display only contains fields or usable attributes.'

def _check_list_display(self, obj):

    if (not isinstance(obj.list_display, (list, tuple))):
        return must_be('a    list    or    tuple', option='list_display', obj=obj, id='admin.E107')
    else:
        return list(chain.from_iterable((self._check_list_display_item(obj, obj.model, item, ('list_display[%d]' % index)) for (index, item) in enumerate(obj.list_display))))
