This callback is called form the Crazyflie API when a Crazyflie
        has been connected and the TOCs have been downloaded.

def _connected(self, link_uri):
        """ This callback is called form the Crazyflie API when a Crazyflie
        has been connected and the TOCs have been downloaded."""
        print('Connected to %s' % link_uri)

        mems = self._cf.mem.get_mems(MemoryElement.TYPE_I2C)
        print('Found {} EEPOM(s)'.format(len(mems)))
        if len(mems) > 0:
            print('Writing default configuration to'
                  ' memory {}'.format(mems[0].id))

            elems = mems[0].elements
            elems['version'] = 1
            elems['pitch_trim'] = 0.0
            elems['roll_trim'] = 0.0
            elems['radio_channel'] = 80
            elems['radio_speed'] = 0
            elems['radio_address'] = 0xE7E7E7E7E7

            mems[0].write_data(self._data_written)