docstr: Test that adding entity in a manual way works correctly.
docstr_tok: ["Test","that","adding","entity","in","a","manual","way","works","correctly","."]
code: def test_add_single(self):
      """Test that adding entity in a manual way works correctly."""
      entities = [
          f"___some_entity{i}_not_present_in_keyed_vectors___"
          for i in range(5)
      ]
      vectors = [
          np.random.randn(self.vectors.vector_size) for _ in range(5)
      ]
  
      # Test `add` on already filled kv.
      for ent, vector in zip(entities, vectors):
          self.vectors.add_vectors(ent, vector)
  
      for ent, vector in zip(entities, vectors):
          self.assertTrue(np.allclose(self.vectors[ent], vector))
  
      # Test `add` on empty kv.
      kv = KeyedVectors(self.vectors.vector_size)
      for ent, vector in zip(entities, vectors):
          kv.add_vectors(ent, vector)
  
      for ent, vector in zip(entities, vectors):
          self.assertTrue(np.allclose(kv[ent], vector))
  
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 21 for calling the TestKeyedVectors obj's underlying member method code with example usage: obj.test_add_single() without return types