code: def _forward_txt_encoding(self, sample_list, fwd_results):
      fwd_results["txt_inds"] = sample_list.text
  
      # binary mask of valid text (question words) vs padding
      fwd_results["txt_mask"] = _get_mask(
          sample_list.text_len, sample_list.text.size(1)
      )
  
imports: import functools
  import logging
  import math
  import torch
  import torch.nn.functional
  from mmf.common.registry import registry
  from mmf.models.base_model import BaseModel
  from mmf.modules.layers import ClassifierLayer
  from mmf.utils.build import build_image_encoder
  from omegaconf import OmegaConf
  from torch import nn
label_desc: Use image node_id 11 for calling the M4C obj's underlying member method code with example usage: obj._forward_txt_encoding(sample_list, fwd_results) without return types