class_docstr: check wrt. the scipy implementation 
code: def xx_test_jensenshannon(self):
      # this distance does not seem to be implemented in scipy
      # vectors should probably be L1 normalized
      self.run_simple_dis_test(
          scipy.spatial.distance.jensenshannon,
          faiss.METRIC_JensenShannon,
      )
  
imports: import numpy
  import faiss
  import unittest
  from common_faiss_tests import get_dataset_2
  import scipy.spatial.distance
label_desc: Use image node_id 9 for calling the TestExtraDistances obj's underlying member method code with example usage: obj.xx_test_jensenshannon() without return types