code: def sequence_mask(lengths, max_len=None):
      """
      Creates a boolean mask from sequence lengths.
      """
      batch_size = lengths.numel()
      max_len = max_len or lengths.max()
      return (
          torch.arange(0, max_len)
          .type_as(lengths)
          .repeat(batch_size, 1)
          .lt(lengths.unsqueeze(1))
      )
  
file_path: deepmatcher/deepmatcher/models/_utils.py
imports: import pdb
  import six
  import deepmatcher
  import torch
  from ..batch import AttrTensor
label_desc: Use image node_id 1 for calling a global function with example usage: sequence_mask(lengths, max_len) and returns: torch