code: def test_builder_to_backend_smoke(self, compute_unit, backend):
      x = np.array([[1, 2, 3], [4, 5, 6]], dtype=np.float32)
      indices = np.array([1, 0], dtype=np.int32)
      input_placeholders = {
          "x": mb.placeholder(shape=x.shape),
          "indices": mb.placeholder(
              shape=indices.shape, dtype=types.int32
          ),
      }
  
      input_values = {"x": x, "indices": indices}
  
      def build(x, indices):
          return [
              mb.gather(x=x, indices=indices, axis=0),
              mb.gather(x=x, indices=indices, axis=1),
              mb.gather(x=x, indices=indices, axis=-2),
              mb.gather(x=x, indices=indices, axis=-1),
              mb.gather(x=x, indices=indices),
              # mb.gather(x=x, indices=1), #shape of scalar indices is incorrect.
              # mb.gather(x=x, indices=1, axis=1), #Scalar index passes on axis=0 but fails on axis=1,
              # Need to handle rank 0 correctly, rdar://73160449
          ]
  
      expected_output_types = [
          (2, 3, types.fp32),
          (2, 2, types.fp32),
          (2, 3, types.fp32),
          (2, 2, types.fp32),
          (2, 3, types.fp32),
          # (3, types.fp32),
      ]
  
      expected_outputs = [
          np.array([[4, 5, 6], [1, 2, 3]], dtype=np.float32),
          np.array([[2, 1], [5, 4]], dtype=np.float32),
          np.array([[4, 5, 6], [1, 2, 3]], dtype=np.float32),
          np.array([[2, 1], [5, 4]], dtype=np.float32),
          np.array([[4, 5, 6], [1, 2, 3]], dtype=np.float32),
          # np.array([4, 5, 6], dtype=np.float32),
      ]
  
      run_compare_builder(
          build,
          input_placeholders,
          input_values,
          expected_output_types,
          expected_outputs,
          compute_unit=compute_unit,
          backend=backend,
      )
  
imports: import itertools
  import numpy
  import pytest
  import coremltools
  from coremltools._deps import _HAS_TF_2, MSG_TF2_NOT_FOUND
  from coremltools.converters.mil.mil import Builder
  from coremltools.converters.mil.mil import types
  from coremltools.converters.mil.mil.ops.tests.iOS14 import backends
  from coremltools.converters.mil.mil.ops.tests.testing_utils import mark_api_breaking, run_compare_builder
  from coremltools.converters.mil.testing_reqs import compute_units
label_desc: Use image node_id 1 for calling the TestGather obj's underlying member method code with example usage: obj.test_builder_to_backend_smoke(compute_unit, backend) and returns: list