tweak stdlib imports to follow Google style guide

Google Python style guide says to import modules.
Clean up all our stdlib imports.  Leave the repo ones alone
for now as that's a much bigger shave.

Change-Id: Ida42fc2ae78b86e6b7a6cbc98f94ca04b295f8cc
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/383714
Reviewed-by: Gavin Mak <gavinmak@google.com>
Commit-Queue: Mike Frysinger <vapier@google.com>
Tested-by: Mike Frysinger <vapier@google.com>
diff --git a/git_config.py b/git_config.py
index 87ed976..971066e 100644
--- a/git_config.py
+++ b/git_config.py
@@ -15,7 +15,7 @@
 import contextlib
 import datetime
 import errno
-from http.client import HTTPException
+import http.client
 import json
 import os
 import re
@@ -650,7 +650,7 @@
                     raise UploadError("%s: %s" % (self.review, str(e)))
                 except urllib.error.URLError as e:
                     raise UploadError("%s: %s" % (self.review, str(e)))
-                except HTTPException as e:
+                except http.client.HTTPException as e:
                     raise UploadError(
                         "%s: %s" % (self.review, e.__class__.__name__)
                     )
diff --git a/release/update_manpages.py b/release/update_manpages.py
index cd2acc0..cb68724 100644
--- a/release/update_manpages.py
+++ b/release/update_manpages.py
@@ -18,8 +18,8 @@
 """
 
 from pathlib import Path
-from functools import partial
 import argparse
+import functools
 import multiprocessing
 import os
 import re
@@ -112,7 +112,9 @@
 
         # Run all cmd in parallel, and wait for them to finish.
         with multiprocessing.Pool() as pool:
-            pool.map(partial(worker, cwd=tempdir, check=True), cmdlist)
+            pool.map(
+                functools.partial(worker, cwd=tempdir, check=True), cmdlist
+            )
 
     for tmp_path in MANDIR.glob("*.1.tmp"):
         path = tmp_path.parent / tmp_path.stem
diff --git a/repo_trace.py b/repo_trace.py
index 4946217..01beaf8 100644
--- a/repo_trace.py
+++ b/repo_trace.py
@@ -20,11 +20,11 @@
 To also include trace outputs in stderr do `repo --trace_to_stderr ...`
 """
 
+import contextlib
 import sys
 import os
 import time
 import tempfile
-from contextlib import ContextDecorator
 
 import platform_utils
 
@@ -68,7 +68,7 @@
     _TRACE_FILE = _GetTraceFile(quiet)
 
 
-class Trace(ContextDecorator):
+class Trace(contextlib.ContextDecorator):
     """Used to capture and save git traces."""
 
     def _time(self):
diff --git a/subcmds/abandon.py b/subcmds/abandon.py
index 896b348..1499c75 100644
--- a/subcmds/abandon.py
+++ b/subcmds/abandon.py
@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from collections import defaultdict
+import collections
 import functools
 import itertools
 import sys
@@ -88,8 +88,8 @@
 
     def Execute(self, opt, args):
         nb = args[0].split()
-        err = defaultdict(list)
-        success = defaultdict(list)
+        err = collections.defaultdict(list)
+        success = collections.defaultdict(list)
         aggregate_errors = []
         all_projects = self.GetProjects(
             args[1:], all_manifests=not opt.this_manifest_only
diff --git a/subcmds/selfupdate.py b/subcmds/selfupdate.py
index 00376b6..983fd63 100644
--- a/subcmds/selfupdate.py
+++ b/subcmds/selfupdate.py
@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from optparse import SUPPRESS_HELP
+import optparse
 import sys
 
 from command import Command, MirrorSafeCommand
@@ -52,7 +52,7 @@
             "--repo-upgraded",
             dest="repo_upgraded",
             action="store_true",
-            help=SUPPRESS_HELP,
+            help=optparse.SUPPRESS_HELP,
         )
 
     def Execute(self, opt, args):
diff --git a/subcmds/sync.py b/subcmds/sync.py
index 159771e..74bc455 100644
--- a/subcmds/sync.py
+++ b/subcmds/sync.py
@@ -19,7 +19,7 @@
 import json
 import multiprocessing
 import netrc
-from optparse import SUPPRESS_HELP
+import optparse
 import os
 import socket
 import sys
@@ -481,7 +481,7 @@
             "--repo-upgraded",
             dest="repo_upgraded",
             action="store_true",
-            help=SUPPRESS_HELP,
+            help=optparse.SUPPRESS_HELP,
         )
 
     def _GetBranch(self, manifest_project):
diff --git a/tests/test_repo_logging.py b/tests/test_repo_logging.py
index ba8a9a9..5402a90 100644
--- a/tests/test_repo_logging.py
+++ b/tests/test_repo_logging.py
@@ -14,7 +14,7 @@
 
 """Unit test for repo_logging module."""
 import unittest
-from unittest.mock import MagicMock
+from unittest import mock
 
 from repo_logging import RepoLogger
 
@@ -30,7 +30,7 @@
             nonlocal result
             result = log.getMessage()
 
-        mock_out = MagicMock()
+        mock_out = mock.MagicMock()
         mock_out.level = 0
         mock_out.handle = mock_handler
         logger.addHandler(mock_out)
@@ -49,7 +49,7 @@
             nonlocal result
             result = log.getMessage()
 
-        mock_out = MagicMock()
+        mock_out = mock.MagicMock()
         mock_out.level = 0
         mock_out.handle = mock_handler
         logger.addHandler(mock_out)
@@ -88,7 +88,7 @@
             nonlocal result
             result.append(log.getMessage())
 
-        mock_out = MagicMock()
+        mock_out = mock.MagicMock()
         mock_out.level = 0
         mock_out.handle = mock_handler
         logger.addHandler(mock_out)
diff --git a/tests/test_wrapper.py b/tests/test_wrapper.py
index 4e8263b..ef4dce1 100644
--- a/tests/test_wrapper.py
+++ b/tests/test_wrapper.py
@@ -14,7 +14,7 @@
 
 """Unittests for the wrapper.py module."""
 
-from io import StringIO
+import io
 import os
 import re
 import sys
@@ -47,8 +47,10 @@
     def test_version(self):
         """Make sure _Version works."""
         with self.assertRaises(SystemExit) as e:
-            with mock.patch("sys.stdout", new_callable=StringIO) as stdout:
-                with mock.patch("sys.stderr", new_callable=StringIO) as stderr:
+            with mock.patch("sys.stdout", new_callable=io.StringIO) as stdout:
+                with mock.patch(
+                    "sys.stderr", new_callable=io.StringIO
+                ) as stderr:
                     self.wrapper._Version()
         self.assertEqual(0, e.exception.code)
         self.assertEqual("", stderr.getvalue())