code: def test_builder_to_backend_smoke_iOS16(
      self, compute_unit, backend, return_indices, sort
  ):
      val = np.array(
          [[-1.0, 2.0, -3.0], [4.0, -5.0, 6.0]], dtype=np.float32
      )
      input_placeholders = {"x": mb.placeholder(shape=val.shape)}
      input_values = {"x": val}
  
      def build(x):
          return mb.topk(
              x=x, k=2, axis=1, return_indices=return_indices, sort=sort
          )
  
      expected_output_types = [
          (2, 2, types.fp32),
          (2, 2, types.int32),
      ]
      expected_outputs = [
          np.array([[2.0, -1.0], [6.0, 4.0]], dtype=np.float32),
          np.array([[1, 0], [2, 0]], dtype=np.float32),
      ]
  
      if not return_indices:
          expected_output_types = expected_output_types[:1]
          expected_outputs = expected_outputs[:1]
  
      run_compare_builder(
          build,
          input_placeholders,
          input_values,
          expected_output_types,
          expected_outputs,
          compute_unit=compute_unit,
          backend=backend,
      )
  
file_path: coremltools/coremltools/converters/mil/mil/ops/tests/iOS16/test_tensor_operation.py
imports: import itertools
  import numpy
  import pytest
  from coremltools.converters.mil import testing_reqs
  from coremltools.converters.mil.mil import Builder
  from coremltools.converters.mil.mil import types
  from coremltools.converters.mil.mil.ops.tests.iOS16 import backends
  from coremltools.converters.mil.mil.ops.tests.testing_utils import run_compare_builder
label_desc: Use image node_id 1 for calling the TestTopK obj's underlying member method code with example usage: obj.test_builder_to_backend_smoke_iOS16(compute_unit, backend, return_indices, sort) and returns: mb