code: def forward(self, _, processed_sample_list):
      mlm_outputs = self.mlm_head(
          processed_sample_list["hs_masked_for_mlm"],
          processed_sample_list=processed_sample_list,
      )
  
      return mlm_outputs
  
file_path: mmf/mmf/models/transformers/heads/mlm.py
imports: import warnings
  from dataclasses import dataclass
  from typing import Dict, List, Optional
  import torch
  from mmf.common.registry import registry
  from mmf.models.transformers.base import BaseTransformerHead
label_desc: Use image node_id 2 for calling the MLMForMultiHeads obj's underlying member method code with example usage: obj.forward(_, processed_sample_list) and returns: mlm_outputs