code: def test_builder_acos_eval(self):
      val = np.array([[-1, -0.5, 0], [0.4, 0.5, 0.8]], dtype=np.float32)
      v = mb.acos(x=val)
      expected_outputs = np.array(
          [
              [3.14159265, 2.0943951, 1.57079633],
              [1.15927948, 1.04719755, 0.64350111],
          ],
          dtype=np.float32,
      )
      np.testing.assert_allclose(
          expected_outputs, v.val, atol=1e-04, rtol=1e-05
      )
  
imports: import itertools
  import numpy
  import pytest
  import scipy
  from coremltools.converters.mil.mil import Builder
  from coremltools.converters.mil.mil import Function, get_new_symbol, types
  from coremltools.converters.mil.mil.ops.tests.iOS14 import backends
  from coremltools.converters.mil.mil.ops.tests.testing_utils import run_compare_builder
  from coremltools.converters.mil.mil.types.symbolic import is_compatible_symbolic_vector
  from coremltools.converters.mil.testing_reqs import compute_units
  from coremltools.converters.mil.testing_utils import ssa_fn
label_desc: Use image node_id 3 for calling the TestElementwiseUnary obj's underlying member method code with example usage: obj.test_builder_acos_eval() without return types