code: def _test_combinations():
      cases = []
  
      identity = lambda x: x
      increment = lambda x: x + 1
  
      def increment_and_square(x):
          y = x + 1
          return y * y
  
      functions = [identity, increment, increment_and_square]
  
      for i, x in enumerate(functions):
          for j, y in enumerate(functions):
              cases.append(("Scalar{}{}".format(i, j), [x, y]))
              for k, z in enumerate(functions):
                  cases.append(
                      ("Scalar{}{}{}".format(i, j, k), [x, y, z])
                  )
  
      with_42 = lambda x: (x, 42)
      swap = lambda x, y: (y, x)
  
      cases.append(("Tuple1", [with_42, swap]))
      cases.append(("Tuple2", [with_42, swap, swap]))
  
      def reduce_fn(x, y):
          name, functions = y
          return x + combinations.combine(
              functions=combinations.NamedObject(name, functions)
          )
  
      return functools.reduce(reduce_fn, cases, [])
  
imports: import functools
  from absl.testing import parameterized
  from tensorflow.python.data.experimental.ops import testing
  from tensorflow.python.data.kernel_tests import test_base
  from tensorflow.python.data.ops import dataset_ops
  from tensorflow.python.data.ops import options
  from tensorflow.python.framework import combinations
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import errors
  from tensorflow.python.framework import ops
  from tensorflow.python.ops import check_ops
  from tensorflow.python.ops import control_flow_ops
  from tensorflow.python.ops import math_ops
  from tensorflow.python.platform import test
label_desc: Use image node_id 1 for calling a global function with example usage: _test_combinations() and returns: functools, unknown, unknown