code: def test_reference(self):
      self.assertTrue(
          (
              np.array([1, 4]) == mux([True, False], [1, 2], [3, 4])[0]
          ).all()
      )
      self.assertTrue(
          (
              np.array([[1], [4]])
              == mux([[True], [False]], [[1], [2]], [[3], [4]])[0]
          ).all()
      )
  
imports: from caffe2.python import core
  import caffe2.python.hypothesis_test_util
  import caffe2.python.serialized_test.serialized_test_util
  from hypothesis import given, settings
  import hypothesis.strategies
  import numpy
  import unittest
label_desc: Use image node_id 1 for calling the TestWhere obj's underlying member method code with example usage: obj.test_reference() without return types