code: def p_expr_pre_incdec(p):
      '''expr : INC variable
              | DEC variable'''
      p[0] = ast.PreIncDecOp(p[1], p[2], lineno=p.lineno(1)f p_expr_pre_incdec(p):
      '''expr : INC variable
              | DEC variable'''
      p[0] = ast.PreIncDecOp(p[1], p[2], lineno=p.lineno(1))
docs: expr : INC variable
              | DEC variable