default boolean isKeywordOnly() {
    final PyAstParameterList parameters = getStubOrPsiParentOfType(PyAstParameterList.class);
    if (parameters == null) {
      return false;
    }
    boolean varargSeen = false;
    for (PyAstParameter param : parameters.getParameters()) {
      if (param == this) {
        break;
      }
      final PyAstNamedParameter named = param.getAsNamed();
      if ((named != null && named.isPositionalContainer()) || param instanceof PyAstSingleStarParameter) {
        varargSeen = true;
        break;
      }
    }
    return varargSeen;
  }
default boolean isKeywordOnly()