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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _check_for_initial_packet_cb(self, data):
 """ Called when first packet arrives from Crazyflie. This is used to determine if we are connected to something that is answering. """

        self.state = State.CONNECTED
        self.link_established.call(self.link_uri)
        self.packet_received.remove_callback(self._check_for_initial_packet_cb)