public void parseParameterList() {
    final SyntaxTreeBuilder.Marker parameterList;
    if (myBuilder.getTokenType() != PyTokenTypes.LPAR) {
      myBuilder.error(message("PARSE.expected.lpar"));
      parameterList = myBuilder.mark(); // To have non-empty parameters list at all the time.
      parameterList.done(PyElementTypes.PARAMETER_LIST);
      return;
    }
    parseParameterListContents(PyTokenTypes.RPAR, true, false);
  }
public void parseParameterList()