Same as sending :py:class:`~pyardrone.at.PCMD` command with progressive
        flag.

def _move(self, roll=0, pitch=0, gaz=0, yaw=0):
        '''
        Same as sending :py:class:`~pyardrone.at.PCMD` command with progressive
        flag.
        '''
        self.send(at.PCMD(at.PCMD.flag.progressive, roll, pitch, gaz, yaw))