docstr: Test most_similar raises KeyError when input is out of vocab.
docstr_tok: ["Test","most_similar","raises","KeyError","when","input","is","out","of","vocab","."]
code: def test_most_similar_raises_keyerror(self):
      """Test most_similar raises KeyError when input is out of vocab."""
      with self.assertRaises(KeyError):
          self.vectors.most_similar("not_in_vocab")
  
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 11 for calling the TestKeyedVectors obj's underlying member method code with example usage: obj.test_most_similar_raises_keyerror() without return types