code: def pull(self, n_id: Optional[Tensor] = None) -> Tensor:
      out = self.emb
      if n_id is not None:
          assert n_id.device == self.emb.device
          out = out.index_select(0, n_id)
      return out.to(device=self._device)
  
file_path: DIG/dig/lsgraph/method/FM.py
imports: import torch
  from torch import nn, Tensor
  from typing import Optional
label_desc: Use image node_id 4 for calling the FeatureMomentum obj's underlying member method code with example usage: obj.pull(n_id) and returns: out