code: def test_slice(self):
      rng = np.random.RandomState(1994)
      rows = 100
      X = rng.randint(3, 7, size=rows)
      X = pd.DataFrame({"f0": X})
      y = rng.randn(rows)
      ridxs = [1, 2, 3, 4, 5, 6]
      m = xgb.DMatrix(X, y)
      sliced = m.slice(ridxs)
  
      assert m.feature_types == sliced.feature_types
  
imports: from typing import Type
  import numpy
  import pytest
  import xgboost
  from xgboost import testing
  from xgboost.core import DataSplitMode
  from xgboost.testing.data import pd_arrow_dtypes, pd_dtypes, run_base_margin_info
label_desc: Use image node_id 3 for calling the TestPandas obj's underlying member method code with example usage: obj.test_slice() without return types