def pcmd(progressive, lr, fb, vv, va):
    """
    Makes the drone move (translate/rotate).

    Parameters:
    progressive -- True: enable progressive commands, False: disable (i.e.
        enable hovering mode)
    lr -- left-right tilt: float [-1..1] negative: left, positive: right
    rb -- front-back tilt: float [-1..1] negative: forwards, positive:
        backwards
    vv -- vertical speed: float [-1..1] negative: go down, positive: rise
    va -- angular speed: float [-1..1] negative: spin left, positive: spin 
        right

    The above float values are a percentage of the maximum speed.
    """
    assert type(progressive) == bool
    assert all(map(lambda x: abs(x) <= 1, (lr, fb, vv, va)))
    return progressive, float(lr), float(fb), float(vv), float(va)