code: def testUnknownCardinality(self):
      ds = dataset_ops.Dataset.from_tensors({"a": 1}).filter(
          lambda x: True
      )
      with self.assertRaisesRegex(
          ValueError,
          "The dataset passed into `pad_to_cardinality` must have a "
          "known cardinalty, but has cardinality -2",
      ):
          ds = ds.apply(pad_to_cardinality(5))
          self.getDatasetOutput(ds)
  
file_path: tensorflow-upstream/tensorflow/python/data/experimental/kernel_tests/pad_to_cardinality_test.py
imports: from absl.testing import parameterized
  from tensorflow.python.data.experimental.ops import pad_to_cardinality
  from tensorflow.python.data.kernel_tests import test_base
  from tensorflow.python.data.ops import dataset_ops
  from tensorflow.python.framework import combinations
  from tensorflow.python.platform import test
label_desc: Use image node_id 4 for calling the PadToCardinalityTest obj's underlying member method code with example usage: obj.testUnknownCardinality() without return types