code: def test_builder_eval(self):
      v = mb.constexpr_sparse_to_dense(
          nonzero_data=np.array([1.0, 2.0, 4.0]),
          mask=np.array([11]).astype(np.uint8),
          shape=np.array(
              [
                  4,
              ]
          ).astype(np.uint32),
      )
      assert v.val is None
      np.testing.assert_allclose(
          np.float32([1.0, 2.0, 0.0, 4.0]),
          v.op.materialized_val_inference(),
      )
  
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.defs.iOS16 import constexpr_ops
  from coremltools.converters.mil.mil.ops.tests.iOS16 import backends
  from coremltools.converters.mil.mil.ops.tests.testing_utils import run_compare_builder
  from coremltools.converters.mil.testing_utils import get_op_types_in_program, ssa_fn
label_desc: Use image node_id 2 for calling the TestConstexprSparseToDense obj's underlying member method code with example usage: obj.test_builder_eval() without return types