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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 is_valid_short_number(numobj):
 """Tests whether a short number matches a valid pattern. If a country calling code is shared by multiple regions, this returns True if it's valid in any of them. Note that this doesn't verify the number is actually in use, which is impossible to tell by just looking at the number itself. See is_valid_short_number_for_region for details. Arguments: numobj - the short number for which we want to test the validity Return whether the short number matches a valid pattern """

    region_codes = region_codes_for_country_code(numobj.country_code)
    region_code = _region_code_for_short_number_from_region_list(numobj, region_codes)
    if len(region_codes) > 1 and region_code is not None:
        # If a matching region had been found for the phone number from among two or more regions,
        # then we have already implicitly verified its validity for that region.
        return True
    return is_valid_short_number_for_region(numobj, region_code)