code: def wrap_expr(self, src: str, dfltChaining: bool) -> str:
          
          diff_binding = self.op_man.diff_binding()
          if diff_binding < 0 or diff_binding == 0 and not dfltChaining:
              return self.parenthesize(src)
          else:
              return src
docs: Wrap `src` in parentheses if neccessary.