docstr: Helper function returns peer that is p hops behind r
docstr_tok: ["Helper","function","returns","peer","that","is","p","hops","behind","r"]
code: def _rotate_backward(self, r: int, p: int) -> int:
      """Helper function returns peer that is p hops behind r"""
      return (r - p) % self.world_size
  
imports: from abc import ABC, abstractmethod
  from math import log
  from typing import List, Optional, Tuple
  import torch
  import torch.distributed
label_desc: Use image node_id 14 for calling the GraphManager obj's underlying member method code with example usage: obj._rotate_backward(r, p) and returns: unknown