diff --git a/demo/dask/cpu_survival.py b/demo/dask/cpu_survival.py
index 629667b1283f..83eddd361a29 100644
--- a/demo/dask/cpu_survival.py
+++ b/demo/dask/cpu_survival.py
@@ -8,9 +8,9 @@
 
 import dask.dataframe as dd
 from dask.distributed import Client, LocalCluster
-from xgboost.dask import DaskDMatrix
 
 import xgboost as xgb
+from xgboost.dask import DaskDMatrix
 
 
 def main(client):
diff --git a/demo/dask/cpu_training.py b/demo/dask/cpu_training.py
index 7fc5d2d1c859..a31e5d2a626d 100644
--- a/demo/dask/cpu_training.py
+++ b/demo/dask/cpu_training.py
@@ -5,9 +5,9 @@
 """
 from dask import array as da
 from dask.distributed import Client, LocalCluster
-from xgboost.dask import DaskDMatrix
 
 import xgboost as xgb
+from xgboost.dask import DaskDMatrix
 
 
 def main(client):
diff --git a/demo/dask/dask_callbacks.py b/demo/dask/dask_callbacks.py
index a80ede01f1cb..408297d9e2f2 100644
--- a/demo/dask/dask_callbacks.py
+++ b/demo/dask/dask_callbacks.py
@@ -6,9 +6,9 @@
 from dask.distributed import Client, LocalCluster
 from dask_ml.datasets import make_regression
 from dask_ml.model_selection import train_test_split
-from xgboost.dask import DaskDMatrix
 
 import xgboost as xgb
+from xgboost.dask import DaskDMatrix
 
 
 def probability_for_going_backward(epoch):
diff --git a/demo/dask/gpu_training.py b/demo/dask/gpu_training.py
index cf09f8e44c5e..23cbfb47c7e2 100644
--- a/demo/dask/gpu_training.py
+++ b/demo/dask/gpu_training.py
@@ -7,10 +7,10 @@
 from dask import dataframe as dd
 from dask.distributed import Client
 from dask_cuda import LocalCUDACluster
-from xgboost.dask import DaskDMatrix
 
 import xgboost as xgb
 from xgboost import dask as dxgb
+from xgboost.dask import DaskDMatrix
 
 
 def using_dask_matrix(client: Client, X, y):
diff --git a/demo/guide-python/spark_estimator_examples.py b/demo/guide-python/spark_estimator_examples.py
index cbc3862e5913..97caef610642 100644
--- a/demo/guide-python/spark_estimator_examples.py
+++ b/demo/guide-python/spark_estimator_examples.py
@@ -10,6 +10,7 @@
 from pyspark.sql import SparkSession
 from pyspark.sql.functions import rand
 from sklearn.model_selection import train_test_split
+
 from xgboost.spark import SparkXGBClassifier, SparkXGBRegressor
 
 spark = SparkSession.builder.master("local[*]").getOrCreate()
diff --git a/demo/nvflare/custom/controller.py b/demo/nvflare/custom/controller.py
index ae2933ad8316..dd3e39f46cf3 100644
--- a/demo/nvflare/custom/controller.py
+++ b/demo/nvflare/custom/controller.py
@@ -4,7 +4,6 @@
 """
 import multiprocessing
 
-import xgboost.federated
 from nvflare.apis.client import Client
 from nvflare.apis.fl_context import FLContext
 from nvflare.apis.impl.controller import Controller, Task
@@ -12,6 +11,8 @@
 from nvflare.apis.signal import Signal
 from trainer import SupportedTasks
 
+import xgboost.federated
+
 
 class XGBoostController(Controller):
     def __init__(self, port: int, world_size: int, server_key_path: str,
diff --git a/python-package/xgboost/spark/core.py b/python-package/xgboost/spark/core.py
index 8a13e88cc150..745c9348fc9a 100644
--- a/python-package/xgboost/spark/core.py
+++ b/python-package/xgboost/spark/core.py
@@ -34,12 +34,12 @@
     ShortType,
 )
 from scipy.special import expit, softmax  # pylint: disable=no-name-in-module
-from xgboost.compat import is_cudf_available
-from xgboost.core import Booster
-from xgboost.training import train as worker_train
 
 import xgboost
 from xgboost import XGBClassifier, XGBRanker, XGBRegressor
+from xgboost.compat import is_cudf_available
+from xgboost.core import Booster
+from xgboost.training import train as worker_train
 
 from .data import (
     _read_csr_matrix_from_unwrapped_spark_vec,
diff --git a/python-package/xgboost/spark/data.py b/python-package/xgboost/spark/data.py
index e5a0eac94ea7..6e2d4c6db255 100644
--- a/python-package/xgboost/spark/data.py
+++ b/python-package/xgboost/spark/data.py
@@ -6,9 +6,9 @@
 import numpy as np
 import pandas as pd
 from scipy.sparse import csr_matrix
-from xgboost.compat import concat
 
 from xgboost import DataIter, DMatrix, QuantileDMatrix, XGBModel
+from xgboost.compat import concat
 
 from .._typing import ArrayLike
 from ..core import _convert_ntree_limit
diff --git a/python-package/xgboost/spark/model.py b/python-package/xgboost/spark/model.py
index 6b050a468357..888bc9cc5de9 100644
--- a/python-package/xgboost/spark/model.py
+++ b/python-package/xgboost/spark/model.py
@@ -8,6 +8,7 @@
 from pyspark import SparkFiles, cloudpickle
 from pyspark.ml.util import DefaultParamsReader, DefaultParamsWriter, MLReader, MLWriter
 from pyspark.sql import SparkSession
+
 from xgboost.core import Booster
 
 from .utils import get_class_name, get_logger
diff --git a/python-package/xgboost/spark/utils.py b/python-package/xgboost/spark/utils.py
index 189396089394..979c40ea9c1a 100644
--- a/python-package/xgboost/spark/utils.py
+++ b/python-package/xgboost/spark/utils.py
@@ -8,9 +8,9 @@
 import pyspark
 from pyspark import BarrierTaskContext, SparkContext
 from pyspark.sql.session import SparkSession
-from xgboost.tracker import RabitTracker
 
 from xgboost import collective
+from xgboost.tracker import RabitTracker
 
 
 def get_class_name(cls: Type) -> str:
diff --git a/python-package/xgboost/testing/__init__.py b/python-package/xgboost/testing/__init__.py
index 23d1731b0d9c..bb13b5523ed2 100644
--- a/python-package/xgboost/testing/__init__.py
+++ b/python-package/xgboost/testing/__init__.py
@@ -34,10 +34,10 @@
 import numpy as np
 import pytest
 from scipy import sparse
-from xgboost.core import ArrayLike
-from xgboost.sklearn import SklObjective
 
 import xgboost as xgb
+from xgboost.core import ArrayLike
+from xgboost.sklearn import SklObjective
 
 hypothesis = pytest.importorskip("hypothesis")
 
diff --git a/python-package/xgboost/testing/dask.py b/python-package/xgboost/testing/dask.py
index e1f7142943fa..8b39ba12269a 100644
--- a/python-package/xgboost/testing/dask.py
+++ b/python-package/xgboost/testing/dask.py
@@ -2,9 +2,9 @@
 import numpy as np
 from dask import array as da
 from distributed import Client
-from xgboost.testing.updater import get_basescore
 
 import xgboost as xgb
+from xgboost.testing.updater import get_basescore
 
 
 def check_init_estimation_clf(tree_method: str, client: Client) -> None:
diff --git a/python-package/xgboost/testing/data.py b/python-package/xgboost/testing/data.py
index 791ffd7ec506..4f79d7358e93 100644
--- a/python-package/xgboost/testing/data.py
+++ b/python-package/xgboost/testing/data.py
@@ -2,6 +2,7 @@
 from typing import Any, Generator, Tuple, Union
 
 import numpy as np
+
 from xgboost.data import pandas_pyarrow_mapper
 
 
diff --git a/python-package/xgboost/testing/shared.py b/python-package/xgboost/testing/shared.py
index 92c5f1e0d6a7..930873163dbc 100644
--- a/python-package/xgboost/testing/shared.py
+++ b/python-package/xgboost/testing/shared.py
@@ -8,9 +8,9 @@
 from typing import Any, Callable, Dict, Type
 
 import numpy as np
-from xgboost._typing import ArrayLike
 
 import xgboost as xgb
+from xgboost._typing import ArrayLike
 
 
 def validate_leaf_output(leaf: np.ndarray, num_parallel_tree: int) -> None:
diff --git a/python-package/xgboost/testing/updater.py b/python-package/xgboost/testing/updater.py
index 05d620088963..4086f92c8ff2 100644
--- a/python-package/xgboost/testing/updater.py
+++ b/python-package/xgboost/testing/updater.py
@@ -4,9 +4,9 @@
 from typing import Dict
 
 import numpy as np
-import xgboost.testing as tm
 
 import xgboost as xgb
+import xgboost.testing as tm
 
 
 def get_basescore(model: xgb.XGBModel) -> float:
@@ -78,6 +78,7 @@ def check_quantile_loss(tree_method: str, weighted: bool) -> None:
     """Test for quantile loss."""
     from sklearn.datasets import make_regression
     from sklearn.metrics import mean_pinball_loss
+
     from xgboost.sklearn import _metric_decorator
 
     n_samples = 4096
diff --git a/tests/ci_build/lint_python.py b/tests/ci_build/lint_python.py
index f5ac1c1c98f3..b3a06b311ff9 100644
--- a/tests/ci_build/lint_python.py
+++ b/tests/ci_build/lint_python.py
@@ -3,12 +3,15 @@
 import subprocess
 import sys
 from multiprocessing import Pool, cpu_count
-from typing import Dict, Tuple
+from typing import Dict, Optional, Tuple
 
 from pylint import epylint
 from test_utils import PY_PACKAGE, ROOT, cd, print_time, record_time
 
 CURDIR = os.path.normpath(os.path.abspath(os.path.dirname(__file__)))
+SRCPATH = os.path.normpath(
+    os.path.join(CURDIR, os.path.pardir, os.path.pardir, "python-package")
+)
 
 
 @record_time
@@ -29,7 +32,7 @@ def run_black(rel_path: str) -> bool:
 
 @record_time
 def run_isort(rel_path: str) -> bool:
-    cmd = ["isort", "--check", "--profile=black", rel_path]
+    cmd = ["isort", f"--src={SRCPATH}", "--profile=black", rel_path]
     ret = subprocess.run(cmd).returncode
     if ret != 0:
         subprocess.run(["isort", "--version"])
diff --git a/tests/python-gpu/test_gpu_data_iterator.py b/tests/python-gpu/test_gpu_data_iterator.py
index 23e495bcc250..4325b63086d8 100644
--- a/tests/python-gpu/test_gpu_data_iterator.py
+++ b/tests/python-gpu/test_gpu_data_iterator.py
@@ -2,6 +2,7 @@
 
 import pytest
 from hypothesis import given, settings, strategies
+
 from xgboost.testing import no_cupy
 
 sys.path.append("tests/python")
diff --git a/tests/python-gpu/test_gpu_eval_metrics.py b/tests/python-gpu/test_gpu_eval_metrics.py
index 2e3b29f99989..6d16aa44e1d7 100644
--- a/tests/python-gpu/test_gpu_eval_metrics.py
+++ b/tests/python-gpu/test_gpu_eval_metrics.py
@@ -1,10 +1,10 @@
 import sys
 
 import pytest
-from xgboost.testing.metrics import check_quantile_error
 
 import xgboost
 from xgboost import testing as tm
+from xgboost.testing.metrics import check_quantile_error
 
 sys.path.append("tests/python")
 import test_eval_metrics as test_em  # noqa
diff --git a/tests/python-gpu/test_gpu_prediction.py b/tests/python-gpu/test_gpu_prediction.py
index 0391784398dd..c4d9abba5f77 100644
--- a/tests/python-gpu/test_gpu_prediction.py
+++ b/tests/python-gpu/test_gpu_prediction.py
@@ -3,10 +3,10 @@
 import numpy as np
 import pytest
 from hypothesis import assume, given, settings, strategies
-from xgboost.compat import PANDAS_INSTALLED
 
 import xgboost as xgb
 from xgboost import testing as tm
+from xgboost.compat import PANDAS_INSTALLED
 
 if PANDAS_INSTALLED:
     from hypothesis.extra.pandas import column, data_frames, range_indexes
diff --git a/tests/python-gpu/test_gpu_updaters.py b/tests/python-gpu/test_gpu_updaters.py
index 23b2fdf00083..e6c837f982ce 100644
--- a/tests/python-gpu/test_gpu_updaters.py
+++ b/tests/python-gpu/test_gpu_updaters.py
@@ -4,11 +4,11 @@
 import numpy as np
 import pytest
 from hypothesis import assume, given, note, settings, strategies
-from xgboost.testing.params import cat_parameter_strategy, hist_parameter_strategy
-from xgboost.testing.updater import check_init_estimation, check_quantile_loss
 
 import xgboost as xgb
 from xgboost import testing as tm
+from xgboost.testing.params import cat_parameter_strategy, hist_parameter_strategy
+from xgboost.testing.updater import check_init_estimation, check_quantile_loss
 
 sys.path.append("tests/python")
 import test_updaters as test_up
diff --git a/tests/python-gpu/test_gpu_with_sklearn.py b/tests/python-gpu/test_gpu_with_sklearn.py
index f26f70b367f4..c9d3ab4ebff7 100644
--- a/tests/python-gpu/test_gpu_with_sklearn.py
+++ b/tests/python-gpu/test_gpu_with_sklearn.py
@@ -5,10 +5,10 @@
 
 import numpy as np
 import pytest
-from xgboost.testing.ranking import run_ranking_qid_df
 
 import xgboost as xgb
 from xgboost import testing as tm
+from xgboost.testing.ranking import run_ranking_qid_df
 
 sys.path.append("tests/python")
 import test_with_sklearn as twskl  # noqa
diff --git a/tests/python/test_data_iterator.py b/tests/python/test_data_iterator.py
index 4b4258a2139d..0590a4954e60 100644
--- a/tests/python/test_data_iterator.py
+++ b/tests/python/test_data_iterator.py
@@ -4,11 +4,11 @@
 import pytest
 from hypothesis import given, settings, strategies
 from scipy.sparse import csr_matrix
-from xgboost.data import SingleBatchInternalIter as SingleBatch
-from xgboost.testing import IteratorForTest, make_batches, non_increasing
 
 import xgboost as xgb
 from xgboost import testing as tm
+from xgboost.data import SingleBatchInternalIter as SingleBatch
+from xgboost.testing import IteratorForTest, make_batches, non_increasing
 
 pytestmark = tm.timeout(30)
 
diff --git a/tests/python/test_dmatrix.py b/tests/python/test_dmatrix.py
index 610a46639928..ef56ff6560c0 100644
--- a/tests/python/test_dmatrix.py
+++ b/tests/python/test_dmatrix.py
@@ -6,10 +6,10 @@
 import scipy.sparse
 from hypothesis import given, settings, strategies
 from scipy.sparse import csr_matrix, rand
-from xgboost.testing.data import np_dtypes
 
 import xgboost as xgb
 from xgboost import testing as tm
+from xgboost.testing.data import np_dtypes
 
 rng = np.random.RandomState(1)
 
diff --git a/tests/python/test_early_stopping.py b/tests/python/test_early_stopping.py
index 000d5e347edc..47f58cbd69c6 100644
--- a/tests/python/test_early_stopping.py
+++ b/tests/python/test_early_stopping.py
@@ -1,9 +1,9 @@
 import numpy as np
 import pytest
-from xgboost.testing.updater import get_basescore
 
 import xgboost as xgb
 from xgboost import testing as tm
+from xgboost.testing.updater import get_basescore
 
 rng = np.random.RandomState(1994)
 
diff --git a/tests/python/test_eval_metrics.py b/tests/python/test_eval_metrics.py
index 7a243edb9f52..ebd0da144d8d 100644
--- a/tests/python/test_eval_metrics.py
+++ b/tests/python/test_eval_metrics.py
@@ -1,9 +1,9 @@
 import numpy as np
 import pytest
-from xgboost.testing.metrics import check_quantile_error
 
 import xgboost as xgb
 from xgboost import testing as tm
+from xgboost.testing.metrics import check_quantile_error
 
 rng = np.random.RandomState(1337)
 
diff --git a/tests/python/test_predict.py b/tests/python/test_predict.py
index 63c0ff9d753b..cb400df87f20 100644
--- a/tests/python/test_predict.py
+++ b/tests/python/test_predict.py
@@ -5,11 +5,11 @@
 import pandas as pd
 import pytest
 from scipy import sparse
-from xgboost.testing.data import np_dtypes, pd_dtypes
-from xgboost.testing.shared import validate_leaf_output
 
 import xgboost as xgb
 from xgboost import testing as tm
+from xgboost.testing.data import np_dtypes, pd_dtypes
+from xgboost.testing.shared import validate_leaf_output
 
 
 def run_threaded_predict(X, rows, predict_func):
diff --git a/tests/python/test_quantile_dmatrix.py b/tests/python/test_quantile_dmatrix.py
index 82815d8830d3..316d0e5f6515 100644
--- a/tests/python/test_quantile_dmatrix.py
+++ b/tests/python/test_quantile_dmatrix.py
@@ -4,6 +4,8 @@
 import pytest
 from hypothesis import given, settings, strategies
 from scipy import sparse
+
+import xgboost as xgb
 from xgboost.testing import (
     IteratorForTest,
     make_batches,
@@ -15,8 +17,6 @@
 )
 from xgboost.testing.data import np_dtypes
 
-import xgboost as xgb
-
 
 class TestQuantileDMatrix:
     def test_basic(self) -> None:
diff --git a/tests/python/test_ranking.py b/tests/python/test_ranking.py
index 6121a202904c..ccbdeff5dcd3 100644
--- a/tests/python/test_ranking.py
+++ b/tests/python/test_ranking.py
@@ -6,10 +6,10 @@
 import pytest
 from hypothesis import given, note, settings
 from scipy.sparse import csr_matrix
-from xgboost.testing.params import lambdarank_parameter_strategy
 
 import xgboost
 from xgboost import testing as tm
+from xgboost.testing.params import lambdarank_parameter_strategy
 
 
 def test_ranking_with_unweighted_data():
diff --git a/tests/python/test_updaters.py b/tests/python/test_updaters.py
index 6ad6e72de2ab..c54fb92675b1 100644
--- a/tests/python/test_updaters.py
+++ b/tests/python/test_updaters.py
@@ -5,6 +5,9 @@
 import numpy as np
 import pytest
 from hypothesis import given, note, settings, strategies
+
+import xgboost as xgb
+from xgboost import testing as tm
 from xgboost.testing.params import (
     cat_parameter_strategy,
     exact_parameter_strategy,
@@ -12,9 +15,6 @@
 )
 from xgboost.testing.updater import check_init_estimation, check_quantile_loss
 
-import xgboost as xgb
-from xgboost import testing as tm
-
 
 def train_result(param, dmat, num_rounds):
     result = {}
diff --git a/tests/python/test_with_pandas.py b/tests/python/test_with_pandas.py
index 99b34c336191..e5783b24d333 100644
--- a/tests/python/test_with_pandas.py
+++ b/tests/python/test_with_pandas.py
@@ -3,10 +3,10 @@
 import numpy as np
 import pytest
 from test_dmatrix import set_base_margin_info
-from xgboost.testing.data import pd_arrow_dtypes, pd_dtypes
 
 import xgboost as xgb
 from xgboost import testing as tm
+from xgboost.testing.data import pd_arrow_dtypes, pd_dtypes
 
 try:
     import pandas as pd
diff --git a/tests/python/test_with_sklearn.py b/tests/python/test_with_sklearn.py
index b905ac78c36b..26e4ad343072 100644
--- a/tests/python/test_with_sklearn.py
+++ b/tests/python/test_with_sklearn.py
@@ -8,12 +8,12 @@
 import numpy as np
 import pytest
 from sklearn.utils.estimator_checks import parametrize_with_checks
-from xgboost.testing.ranking import run_ranking_qid_df
-from xgboost.testing.shared import get_feature_weights, validate_data_initialization
-from xgboost.testing.updater import get_basescore
 
 import xgboost as xgb
 from xgboost import testing as tm
+from xgboost.testing.ranking import run_ranking_qid_df
+from xgboost.testing.shared import get_feature_weights, validate_data_initialization
+from xgboost.testing.updater import get_basescore
 
 rng = np.random.RandomState(1994)
 pytestmark = [pytest.mark.skipif(**tm.no_sklearn()), tm.timeout(30)]
diff --git a/tests/test_distributed/test_federated/test_federated.py b/tests/test_distributed/test_federated/test_federated.py
index a534b81210ce..9b8e559157d9 100644
--- a/tests/test_distributed/test_federated/test_federated.py
+++ b/tests/test_distributed/test_federated/test_federated.py
@@ -3,9 +3,8 @@
 import sys
 import time
 
-import xgboost.federated
-
 import xgboost as xgb
+import xgboost.federated
 
 SERVER_KEY = 'server-key.pem'
 SERVER_CERT = 'server-cert.pem'
diff --git a/tests/test_distributed/test_gpu_with_dask/test_gpu_with_dask.py b/tests/test_distributed/test_gpu_with_dask/test_gpu_with_dask.py
index cf36e92b2f20..2e3b031c1d4b 100644
--- a/tests/test_distributed/test_gpu_with_dask/test_gpu_with_dask.py
+++ b/tests/test_distributed/test_gpu_with_dask/test_gpu_with_dask.py
@@ -10,10 +10,10 @@
 import pytest
 from hypothesis import given, note, settings, strategies
 from hypothesis._settings import duration
-from xgboost.testing.params import hist_parameter_strategy
 
 import xgboost as xgb
 from xgboost import testing as tm
+from xgboost.testing.params import hist_parameter_strategy
 
 pytestmark = [
     pytest.mark.skipif(**tm.no_dask()),
@@ -42,9 +42,9 @@
     from dask import array as da
     from dask.distributed import Client
     from dask_cuda import LocalCUDACluster
-    from xgboost.testing.dask import check_init_estimation
 
     from xgboost import dask as dxgb
+    from xgboost.testing.dask import check_init_estimation
 except ImportError:
     pass
 
diff --git a/tests/test_distributed/test_gpu_with_spark/test_gpu_spark.py b/tests/test_distributed/test_gpu_with_spark/test_gpu_spark.py
index db0650f09537..1f986f96ea10 100644
--- a/tests/test_distributed/test_gpu_with_spark/test_gpu_spark.py
+++ b/tests/test_distributed/test_gpu_with_spark/test_gpu_spark.py
@@ -12,6 +12,7 @@
 from pyspark.ml.linalg import Vectors
 from pyspark.ml.tuning import CrossValidator, ParamGridBuilder
 from pyspark.sql import SparkSession
+
 from xgboost.spark import SparkXGBClassifier, SparkXGBRegressor
 
 gpu_discovery_script_path = "tests/test_distributed/test_gpu_with_spark/discover_gpu.sh"
diff --git a/tests/test_distributed/test_with_dask/test_with_dask.py b/tests/test_distributed/test_with_dask/test_with_dask.py
index ba76c04dbf89..369dcd421757 100644
--- a/tests/test_distributed/test_with_dask/test_with_dask.py
+++ b/tests/test_distributed/test_with_dask/test_with_dask.py
@@ -21,6 +21,9 @@
 import sklearn
 from hypothesis import HealthCheck, given, note, settings
 from sklearn.datasets import make_classification, make_regression
+
+import xgboost as xgb
+from xgboost import testing as tm
 from xgboost.data import _is_cudf_df
 from xgboost.testing.params import hist_parameter_strategy
 from xgboost.testing.shared import (
@@ -29,9 +32,6 @@
     validate_leaf_output,
 )
 
-import xgboost as xgb
-from xgboost import testing as tm
-
 pytestmark = [tm.timeout(60), pytest.mark.skipif(**tm.no_dask())]
 
 import dask
@@ -39,6 +39,7 @@
 import dask.dataframe as dd
 from distributed import Client, LocalCluster
 from toolz import sliding_window  # dependency of dask
+
 from xgboost.dask import DaskDMatrix
 from xgboost.testing.dask import check_init_estimation
 
diff --git a/tests/test_distributed/test_with_spark/test_data.py b/tests/test_distributed/test_with_spark/test_data.py
index af6732df7f86..b08fcdf1d110 100644
--- a/tests/test_distributed/test_with_spark/test_data.py
+++ b/tests/test_distributed/test_with_spark/test_data.py
@@ -8,6 +8,7 @@
 
 pytestmark = [pytest.mark.skipif(**tm.no_spark())]
 
+from xgboost import DMatrix, QuantileDMatrix
 from xgboost.spark.data import (
     _read_csr_matrix_from_unwrapped_spark_vec,
     alias,
@@ -15,8 +16,6 @@
     stack_series,
 )
 
-from xgboost import DMatrix, QuantileDMatrix
-
 
 def test_stack() -> None:
     a = pd.DataFrame({"a": [[1, 2], [3, 4]]})
diff --git a/tests/test_distributed/test_with_spark/test_spark_local.py b/tests/test_distributed/test_with_spark/test_spark_local.py
index f6e5ceaf3940..33d60badce3f 100644
--- a/tests/test_distributed/test_with_spark/test_spark_local.py
+++ b/tests/test_distributed/test_with_spark/test_spark_local.py
@@ -8,10 +8,10 @@
 
 import numpy as np
 import pytest
-from xgboost.spark.data import pred_contribs
 
 import xgboost as xgb
 from xgboost import testing as tm
+from xgboost.spark.data import pred_contribs
 
 pytestmark = [tm.timeout(60), pytest.mark.skipif(**tm.no_spark())]
 
@@ -23,6 +23,8 @@
 from pyspark.ml.tuning import CrossValidator, ParamGridBuilder
 from pyspark.sql import SparkSession
 from pyspark.sql import functions as spark_sql_func
+
+from xgboost import XGBClassifier, XGBModel, XGBRegressor
 from xgboost.spark import (
     SparkXGBClassifier,
     SparkXGBClassifierModel,
@@ -32,8 +34,6 @@
 )
 from xgboost.spark.core import _non_booster_params
 
-from xgboost import XGBClassifier, XGBModel, XGBRegressor
-
 from .utils import SparkTestCase
 
 logging.getLogger("py4j").setLevel(logging.INFO)
diff --git a/tests/test_distributed/test_with_spark/test_spark_local_cluster.py b/tests/test_distributed/test_with_spark/test_spark_local_cluster.py
index cd8acbb6e463..56003082fe3e 100644
--- a/tests/test_distributed/test_with_spark/test_spark_local_cluster.py
+++ b/tests/test_distributed/test_with_spark/test_spark_local_cluster.py
@@ -11,6 +11,7 @@
 pytestmark = pytest.mark.skipif(**tm.no_spark())
 
 from pyspark.ml.linalg import Vectors
+
 from xgboost.spark import SparkXGBClassifier, SparkXGBRegressor
 from xgboost.spark.utils import _get_max_num_concurrent_tasks
 
diff --git a/tests/test_distributed/test_with_spark/utils.py b/tests/test_distributed/test_with_spark/utils.py
index 847316fea5aa..adc6b6069ba3 100644
--- a/tests/test_distributed/test_with_spark/utils.py
+++ b/tests/test_distributed/test_with_spark/utils.py
@@ -13,6 +13,7 @@
 pytestmark = [pytest.mark.skipif(**tm.no_spark())]
 
 from pyspark.sql import SparkSession
+
 from xgboost.spark.utils import _get_default_params_from_func