class_docstr: Divide tokens equally among the tensor parallel ranks
code: def backward(ctx, input_):
      return _gather_tokens(input_, ctx.dim), None
  
file_path: deepspeed/deepspeed/moe/mappings.py
imports: import torch
  import deepspeed
label_desc: Use image node_id 3 for calling the _DropTokens obj's underlying member method code with example usage: obj.backward(ctx, input_) and returns: _gather_tokens,  None