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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 calculate_down_moves(low_data):
 """ Down Move. Formula: DWNMOVE = Lt-1 - Lt """

    down_moves = [low_data[idx-1] - low_data[idx] for idx in range(1, len(low_data))]
    return [np.nan] + down_moves