def _connection_failed(self, link_uri, msg):
        """Callback when connection initial connection fails (i.e no Crazyflie
        at the speficied address)"""
        print('Connection to %s failed: %s' % (link_uri, msg))
        self.is_connected = False
Callback when connection initial connection fails (i.e no Crazyflie
        at the speficied address)