docs: def parse_item(self, key, value, flags: Flags) -> Optional[TransItem]:
          """
          Parse an item (and more specifically its key).
          """
  
          parts = key.split('+')
          pure_key = parts[0]
  
          try:
              if len(parts) == 2:
                  index = int(parts[1])
              elif len(parts) > 2:
                  return
              else:
                  index = 1
          except (ValueError, TypeError):
              return
  
          if index < 1:
              return
  
          return TransItem(
              key=pure_key,
              index=index,
              value=value,
              flags=flags,
          )