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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 _gcd_array(X):
 """ Return the largest real value h such that all elements in x are integer multiples of h. """

    greatest_common_divisor = 0.0
    for x in X:
        greatest_common_divisor = _gcd(greatest_common_divisor, x)

    return greatest_common_divisor