code: def testMultiIndex(self):
      num_dims = 3
      input_array = _input_array(num_dims=num_dims)
      # Also tests [].
      for i in range(num_dims + 1):
          for permutation in itertools.permutations(range(num_dims), i):
              self._testMultipleReduceJoin(
                  input_array, axis=permutation
              )
  
imports: import itertools
  import numpy
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import string_ops
  from tensorflow.python.platform import test
label_desc: Use image node_id 12 for calling the ReduceJoinTest obj's underlying member method code with example usage: obj.testMultiIndex() without return types