code: def test_binary_nuniques_checked(self):
      with self.assertRaises(Exception):
          ot_distance(pd.Series([1, 2, 3], pd.Series(), mode="binary"))
  
imports: import numpy
  import pandas
  from aif360.metrics.ot_metric import _normalize, _transform, _evaluate
  from aif360.sklearn.metrics import ot_distance
  from ot import emd2
  import unittest
  from unittest import TestCase
label_desc: Use image node_id 4 for calling the TestOtBiasScan obj's underlying member method code with example usage: obj.test_binary_nuniques_checked() without return types