@Override
  @Nullable
  default PyAstExpression getDefaultValue() {
    final ASTNode[] nodes = getNode().getChildren(PythonDialectsTokenSetProvider.getInstance().getExpressionTokens());
    if (nodes.length > 0) {
      return (PyAstExpression)nodes[0].getPsi();
    }
    return null;
  }
@Override
  @Nullable
  default PyAstExpression getDefaultValue()