'Pass a callback function that will be called when a published
message is rejected and returned by the server via `Basic.Return`.
:param callable callback: The method to call on callback with the
signature callback(channel, method, properties, body), where
channel: pika.Channel
method: pika.spec.Basic.Return
properties: pika.spec.BasicProperties
body: str, unicode, or bytes (python 3.x)'

def add_on_return_callback(self, callback):

    self._impl.add_on_return_callback((lambda _channel, method, properties, body: self._add_pending_event(_ReturnedMessageEvt(callback, self, method, properties, body))))
