Require isort on all Python files. (#8420)

dev/prepare_jvm_release.py

@@ -1,16 +1,17 @@
-import re
-import os
-import sys
-import platform
-import errno
 import argparse
-import subprocess
+import errno
 import glob
+import os
+import platform
+import re
 import shutil
+import subprocess
+import sys
 import tempfile
 import zipfile
-from urllib.request import urlretrieve
 from contextlib import contextmanager
+from urllib.request import urlretrieve
+
 
 def normpath(path):
     """Normalize UNIX path to a native path."""

dev/query_contributors.py

@@ -1,10 +1,11 @@
 """Query list of all contributors and reviewers in a release"""
 
-from sh.contrib import git
-import sys
-import re
-import requests
 import json
+import re
+import sys
+
+import requests
+from sh.contrib import git
 
 if len(sys.argv) != 5:
     print(f'Usage: {sys.argv[0]} [starting commit/tag] [ending commit/tag] [GitHub username] ' +

dev/release-py-r.py

@@ -2,14 +2,15 @@
 
 tqdm, sh are required to run this script.
 """
-from urllib.request import urlretrieve
 import argparse
-from typing import List, Optional
-from sh.contrib import git
-from packaging import version
-import subprocess
-import tqdm
 import os
+import subprocess
+from typing import List, Optional
+from urllib.request import urlretrieve
+
+import tqdm
+from packaging import version
+from sh.contrib import git
 
 # The package building is managed by Jenkins CI.
 PREFIX = "https://s3-us-west-2.amazonaws.com/xgboost-nightly-builds/release_"