docstr: Test most_similar returns correct results when `topn` is specified.
docstr_tok: ["Test","most_similar","returns","correct","results","when","`","topn","`","is","specified","."]
code: def test_most_similar_topn(self):
      """Test most_similar returns correct results when `topn` is specified."""
      self.assertEqual(len(self.vectors.most_similar("war", topn=5)), 5)
      self.assertEqual(
          len(self.vectors.most_similar("war", topn=10)), 10
      )
  
      predicted = self.vectors.most_similar("war", topn=None)
      self.assertEqual(len(predicted), len(self.vectors))
  
      predicted = self.vectors.most_similar("war", topn=0)
      self.assertEqual(len(predicted), 0)
  
      predicted = self.vectors.most_similar("war", topn=np.uint8(0))
      self.assertEqual(len(predicted), 0)
  
imports: import functools
  import logging
  import unittest
  import numpy
  from gensim.models.keyedvectors import KeyedVectors, REAL, pseudorandom_weak_vector
  from gensim.test.utils import datapath
  import gensim.models.keyedvectors
label_desc: Use image node_id 9 for calling the TestKeyedVectors obj's underlying member method code with example usage: obj.test_most_similar_topn() without return types