code: def _check_region_for_parsing(number, default_region):
      
      if not _is_valid_region_code(default_region):
          # If the number is None or empty, we can't infer the region.
          if number is None or len(number) == 0:
              return False
          match = _PLUS_CHARS_PATTERN.match(number)
          if match is None:
              return False
      return True
docs: Checks to see that the region code used is valid, or if it is not
      valid, that the number to parse starts with a + symbol so that we can
      attempt to infer the region from the number.  Returns False if it cannot
      use the region provided and the region cannot be inferred.