code: def testSliceKeysToNumpyOverall(self):
      actual = slicer.slice_keys_to_numpy_array([()])
      self.assertIsInstance(actual, np.ndarray)
      self.assertEqual(actual.dtype, object)
      self.assertEqual(actual.shape, (1,))
      self.assertEqual(actual[0], ())
  
imports: from absl.testing import parameterized
  import apache_beam
  from apache_beam.testing import util
  import numpy
  import six
  import tensorflow
  from tensorflow_model_analysis import constants
  from tensorflow_model_analysis.api import types
  from tensorflow_model_analysis.eval_saved_model import testutil
  from tensorflow_model_analysis.extractors import slice_key_extractor
  from tensorflow_model_analysis.post_export_metrics import metric_keys
  from tensorflow_model_analysis.proto import config_pb2
  from tensorflow_model_analysis.proto import metrics_for_slice_pb2
  from tensorflow_model_analysis.slicer import slicer_lib
  from google.protobuf import text_format
label_desc: Use image node_id 14 for calling the SlicerTest obj's underlying member method code with example usage: obj.testSliceKeysToNumpyOverall() without return types