docs: void get(
      Object value,
      MatchSpaceKey msg,
      EvalCache cache,
      Object contextValue,
      SearchResults result)
      throws MatchingException, BadMessageFormatMatchingException
    {
      if (value == null && msg != null)
        value = getValue(msg, contextValue);
      if (value == null)
      {
        if (nullChild != null)
          nullChild.get(null, msg, cache, contextValue, result);
      }
      else
      {
        handleGet(value, msg, cache, contextValue, result);
        if (notNullChild != null)
          notNullChild.get(null, msg, cache, contextValue, result);
      }
      super.get(null, msg, cache, contextValue, result);
    }