docs: def _year_expand(s):
          """ Parses a year or dash-delimeted year range
          """
          regex = r"^((?:19|20)\d{2})?(\s*-\s*)?((?:19|20)\d{2})?$"
          try:
              start, dash, end = match(regex, ustr(s)).groups()
              start = start or 1900
              end = end or 2099
          except AttributeError:
              return 1900, 2099
          return (int(start), int(end)) if dash else (int(start), int(start))