parameters: (p)
docstring: expression : LPAREN expression RPAREN
docstring_summary: expression : LPAREN expression RPAREN
docstring_tokens: expression : LPAREN expression RPAREN
function: def p_expression_group(p):
      'expression : LPAREN expression RPAREN'
      p[0] = p[2]
function_tokens: def p_expression_group ( p ) : p [ 0 ] = p [ 2 ]