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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 region_code_for_number(numobj):
 """Returns the region where a phone number is from. This could be used for geocoding at the region level. Only guarantees correct results for valid, full numbers (not short-codes, or invalid numbers). Arguments: numobj -- The phone number object whose origin we want to know Returns the region where the phone number is from, or None if no region matches this calling code. """

    country_code = numobj.country_code
    regions = COUNTRY_CODE_TO_REGION_CODE.get(country_code, None)
    if regions is None:
        return None

    if len(regions) == 1:
        return regions[0]
    else:
        return _region_code_for_number_from_list(numobj, regions)