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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 fast_median(a):
 """Fast median operation for masked array using 50th-percentile """

    a = checkma(a)
    #return scoreatpercentile(a.compressed(), 50)
    if a.count() > 0:
        out = np.percentile(a.compressed(), 50)
    else:
        out = np.ma.masked
    return out