code: def diff_binding(self) -> int:
          
          try:
              prev_op, prev_op_binding = self.nested_ops[-2]
          except IndexError:
              prev_op, prev_op_binding = None, 0
          try:
              curr_op, curr_op_binding = self.nested_ops[-1]
          except IndexError:
              curr_op, curr_op_binding = None, 0
          # special case
          if prev_op is ast.Pow and isinstance(curr_op, (ast.Invert, ast.USub)):
              return 1
          # print(prev_op, prev_op_binding, curr_op, curr_op_binding)
          return curr_op_binding - prev_op_binding
docs: Return the difference betweens the binding levels of the current
          and the previous operator.