code: def unflatten(list_, lengths):
      assert len(list_) == sum(lengths)
      i = 0
      ret = []
      for l in lengths:
          ret.append(list_[i : i + l])
          i += l
      return ret
  
file_path: audio/examples/tutorials/ctc_forced_alignment_api_tutorial.py
imports: import torch
  import torchaudio
  import IPython
  import matplotlib.pyplot
  import torchaudio.functional
label_desc: Use image node_id 3 for calling a global function with example usage: unflatten(list_, lengths) and returns: ret