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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 running_coordination_number(coordinates_a, coordinates_b, periodic, binsize=0.002, cutoff=1.5):
 """This is the cumulative radial distribution function, also called running coordination number"""

    x, y = rdf(coordinates_a,
               coordinates_b,
               periodic=periodic,
               normalize=False,
               binsize=binsize,
               cutoff=cutoff)
    y = y.astype('float32') / len(coordinates_a)
    y = np.cumsum(y)
    return x, y