docstr: Test similarity returns expected value for two nodes, and for identical nodes.
code: def test_similarity(self):
      """Test similarity returns expected value for two nodes, and for identical nodes."""
      self.assertTrue(
          np.allclose(
              self.vectors.similarity("dog.n.01", "dog.n.01"), 1
          )
      )
      self.assertTrue(
          np.allclose(
              self.vectors.similarity("dog.n.01", "mammal.n.01"),
              0.180901358,
          )
      )
  
imports: import logging
  import os
  import tempfile
  import unittest
  import numpy
  from gensim.models.poincare import PoincareRelations, PoincareModel, PoincareKeyedVectors
  from gensim.test.utils import datapath
label_desc: Use image node_id 17 for calling the TestPoincareKeyedVectors obj's underlying member method code with example usage: obj.test_similarity() without return types