code: def test_lead():
      assert len(DOC_1.extract_lead(nsents=1)) == 1
      assert len(DOC_1.extract_lead(nsents=2)) == 2
      assert len(DOC_1.extract_lead(nsents=50)) == DOC_1.nsents
  
imports: import re
  from unittest import mock
  import pytest
  import spacy
  import numpy
  from fakeredis import FakeRedis
  from textpipe.doc import Doc, TextpipeMissingModelException, RedisIDFWeightingMismatchException
  from textpipe.wrappers import RedisKeyedVectors
label_desc: Use image node_id 16 for calling a global function with example usage: test_lead() without return types