'Current channel if the object is bound.'

@property
def channel(self):

    channel = self._channel
    if (channel is None):
        raise NotBoundError(u"Can't    call    method    on    {0}    not    bound    to    a    channel".format(type(self).__name__))
    if isinstance(channel, ChannelPromise):
        channel = self._channel = channel()
    return channel
