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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 _get_nr_prefix(i):
 """ Helper function for looking up the derived name prefix associated with a Unicode scalar value. :param i: Unicode scalar value. :return: String with the derived name prefix. """

    for lookup_range, prefix_string in _nr_prefix_strings.items():
        if i in lookup_range:
            return prefix_string
    raise ValueError("No prefix string associated with {0}!".format(i))