code: protected Parser parser(Key jobKey) {
      ParserProvider pp = ParserService.INSTANCE.getByInfo(_parse_type);
      if (pp != null) {
        return pp.createParser(this, jobKey);
      }
  
      throw new H2OIllegalArgumentException("Unknown file type.  Parse cannot be completed.",
            "Attempted to invoke a parser for ParseType:" + _parse_type + ", which doesn't exist.");
    }
docs: This is a single entry-point to create a parser.
  
  Should be override in subclasses.