'Acknowledge a message by delivery_tag.
Acknowledges a message referenced by delivery_tag. Messages can
only be ACKed using :meth:`basic_ack` if they were acquired using
:meth:`basic_consume`. This is the ACKing portion of the
asynchronous read behavior.
Internally, this method uses the :class:`QoS` object, which stores
messages and is responsible for the ACKing.
:param delivery_tag: The delivery tag associated with the message
to be acknowledged.
:type delivery_tag: uuid.UUID
:param multiple: not implemented. If set to True an AssertionError
is raised.
:type multiple: bool'

def basic_ack(self, delivery_tag, multiple=False):

    assert (multiple is False)
    self.qos.ack(delivery_tag)
