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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 area_difference(item_a, time_a, item_b, time_b, max_value):
 """ RMS Difference in object areas. Args: item_a: STObject from the first set in ObjectMatcher time_a: Time integer being evaluated item_b: STObject from the second set in ObjectMatcher time_b: Time integer being evaluated max_value: Maximum distance value used as scaling value and upper constraint. Returns: Distance value between 0 and 1. """

    size_a = item_a.size(time_a)
    size_b = item_b.size(time_b)
    diff = np.sqrt((size_a - size_b) ** 2)
    return np.minimum(diff, max_value) / float(max_value)