docs: def parse_accept_header(header):
      """Parse accept headers."""
      result = []
      for match in accept_re.finditer(header):
          quality = match.group(2)
          if not quality:
              quality = 1
          else:
              quality = max(min(float(quality), 1), 0)
          result.append((match.group(1), quality))
      return result