code: def forward_lengths(self, lengths):
      return make_pad_mask(lengths)
  
file_path: espnet/test/test_nets_utils.py
imports: import pytest
  import torch
  from espnet.nets.pytorch_backend.nets_utils import make_pad_mask, trim_by_ctc_posterior
label_desc: Use image node_id 3 for calling the MakePadMaskTest obj's underlying member method code with example usage: obj.forward_lengths(lengths) and returns: make_pad_mask