docstr: Test add_silence_to_alignments function.
code: def test_add_silence_to_alignments(self, alignments, words):
      """
      Test add_silence_to_alignments function.
      """
      audio_manifest = {
          "audio_filepath": "test.wav",
          "alignments": alignments,
          "words": words,
      }
      audio_manifest = add_silence_to_alignments(audio_manifest)
      if words[0] == "":
          assert audio_manifest["alignments"] == [0.0] + alignments
          assert audio_manifest["words"] == [""] + words
      else:
          assert audio_manifest["alignments"] == alignments
          assert audio_manifest["words"] == words
  
imports: import os
  import numpy
  import pytest
  import torch
  from omegaconf import DictConfig
  from nemo.collections.asr.parts.utils.data_simulation_utils import DataAnnotator, SpeechSampler, add_silence_to_alignments, binary_search_alignments, get_cleaned_base_path, get_split_points_in_alignments, normalize_audio, read_noise_manifest
  from nemo.collections.asr.parts.utils.manifest_utils import get_ctm_line
label_desc: Use image node_id 5 for calling the TestDataSimulatorUtils obj's underlying member method code with example usage: obj.test_add_silence_to_alignments(alignments, words) without return types