code: def test_inputs(self):
      # checking empty inputs
      vec_1 = []
      vec_2 = []
      result = matutils.hellinger(vec_1, vec_2)
      expected = 0.0
      self.assertEqual(expected, result)
  
      # checking np array and list input
      vec_1 = np.array([])
      vec_2 = []
      result = matutils.hellinger(vec_1, vec_2)
      expected = 0.0
      self.assertEqual(expected, result)
  
      # checking scipy csr matrix and list input
      vec_1 = csr_matrix([])
      vec_2 = []
      result = matutils.hellinger(vec_1, vec_2)
      expected = 0.0
      self.assertEqual(expected, result)
  
imports: import logging
  import unittest
  from gensim import matutils
  from scipy.sparse import csr_matrix
  import numpy
  import math
  from gensim.corpora.mmcorpus import MmCorpus
  from gensim.models import ldamodel
  from gensim.test.utils import datapath, common_dictionary, common_corpus
label_desc: Use image node_id 2 for calling the TestHellinger obj's underlying member method code with example usage: obj.test_inputs() without return types