code: def testGetSelectionMask(
      self,
      masking_inputs,
      expected_selected_items,
      unselectable_ids=None,
      axis=1,
      shuffle_fn="",
      description="",
  ):
      shuffle_fn = (
          functools.partial(array_ops.reverse, axis=[-1])
          if shuffle_fn == "reverse"
          else array_ops.identity
      )
      masking_inputs = ragged_factory_ops.constant(masking_inputs)
      item_selector = item_selector_ops.RandomItemSelector(
          max_selections_per_batch=2,
          selection_rate=1,
          shuffle_fn=shuffle_fn,
          unselectable_ids=unselectable_ids,
      )
      selection_mask = item_selector.get_selection_mask(
          masking_inputs, axis
      )
      selected_items = ragged_array_ops.boolean_mask(
          masking_inputs, selection_mask
      )
      self.assertAllEqual(selected_items, expected_selected_items)
  
imports: import functools
  from absl.testing import parameterized
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops.ragged import ragged_array_ops
  from tensorflow.python.ops.ragged import ragged_factory_ops
  from tensorflow.python.platform import test
  from tensorflow_text.python.ops import item_selector_ops
label_desc: Use image node_id 1 for calling the RandomItemSelectorTest obj's underlying member method code with example usage: obj.testGetSelectionMask(masking_inputs, expected_selected_items, unselectable_ids, axis, shuffle_fn, description) without return types