def _self_referential_fk(klass_model):
for f in klass_model._meta.concrete_fields:<EOL><INDENT>if f.related_model:<EOL><INDENT>if issubclass(klass_model, f.related_model):<EOL><INDENT>return f.attname<EOL><DEDENT><DEDENT><DEDENT>return None<EOL>
Return whether this model has a self ref FK, and the name for the field