def requestImage(self):
    self._image_callback = defer.Deferred()
    self.transport.write(((b'I' + self._camera_id) + b'\n'))
    return self._image_callback
def requestImage(self):
    self._image_callback = defer.Deferred()
    self.transport.write(((b'I' + self._camera_id) + b'\n'))
    return self._image_callback