def METHOD_NAME(self,
                      levels,
                      expected_num_levels,
                      expected_shapes,
                      expected_chunks):
    self.assertIsInstance(levels, list)
    self.assertEqual(expected_num_levels, len(levels))
    for i in range(expected_num_levels):
        msg = f"at index {i}"
        self.assertIsInstance(levels[i], xr.Dataset, msg=msg)
        self.assertEqual(2, len(levels[i].data_vars), msg=msg)
        self.assertIn("a", levels[i], msg=msg)
        self.assertIn("b", levels[i], msg=msg)
    for i in range(expected_num_levels):
        msg = f"at index {i}"
        self.assertEqual(expected_shapes[i], levels[i]["a"].shape,
                         msg=msg)
        self.assertEqual(expected_shapes[i], levels[i]["b"].shape,
                         msg=msg)
    for i in range(expected_num_levels):
        msg = f"at index {i}"
        self.assertEqual(expected_chunks[i], levels[i]["a"].chunks,
                         msg=msg)
        self.assertEqual(expected_chunks[i], levels[i]["b"].chunks,
                         msg=msg)