code: def _match_national_number(number, number_desc, allow_prefix_match):
      
      # We don't want to consider it a prefix match when matching non-empty input against an empty
      # pattern.
      if number_desc is None or number_desc.national_number_pattern is None or len(number_desc.national_number_pattern) == 0:
          return False
      return _match(number, re.compile(number_desc.national_number_pattern), allow_prefix_match)
docs: Returns whether the given national number (a string containing only decimal digits) matches
      the national number pattern defined in the given PhoneNumberDesc object.