Fix style in tools/auto_bisect.

tools/auto_bisect/bisect_utils.py

Index: tools/auto_bisect/bisect_utils.py
diff --git a/tools/auto_bisect/bisect_utils.py b/tools/auto_bisect/bisect_utils.py
index 8d7dbd5357f0259eb107382d3a170fa2fb17744e..f9f0668ec222142dc296f4db53b60cb25c2776c5 100644
--- a/tools/auto_bisect/bisect_utils.py
+++ b/tools/auto_bisect/bisect_utils.py
@@ -318,7 +318,6 @@ def RunGClientAndCreateConfig(opts, custom_deps=None, cwd=None):
   return return_code
 
 
-
 def OnAccessError(func, path, _):
   """Error handler for shutil.rmtree.
 
@@ -424,7 +423,7 @@ def CheckRunGit(command, cwd=None):
   Returns:
     A tuple of the output and return code.
   """
-  (output, return_code) = RunGit(command, cwd=cwd)
+  output, return_code = RunGit(command, cwd=cwd)
 
   assert not return_code, 'An error occurred while running'\
                           ' "git %s"' % ' '.join(command)
@@ -456,8 +455,7 @@ def CreateBisectDirectoryAndSetupDepot(opts, custom_deps):
   if CheckIfBisectDepotExists(opts):
     path_to_dir = os.path.join(os.path.abspath(opts.working_directory),
                                BISECT_DIR, 'src')
-    (output, _) = RunGit(['rev-parse', '--is-inside-work-tree'],
-                         cwd=path_to_dir)
+    output, _ = RunGit(['rev-parse', '--is-inside-work-tree'], cwd=path_to_dir)
     if output.strip() == 'true':
       # Before checking out master, cleanup up any leftover index.lock files.
       _CleanupPreviousGitRuns(path_to_dir)
@@ -508,9 +506,10 @@ def RunProcessAndRetrieveOutput(command, cwd=None):
 
   # On Windows, use shell=True to get PATH interpretation.
   shell = IsWindowsHost()
-  proc = subprocess.Popen(command, shell=shell, stdout=subprocess.PIPE,
+  proc = subprocess.Popen(
+      command, shell=shell, stdout=subprocess.PIPE,
       stderr=subprocess.STDOUT)
-  (output, _) = proc.communicate()
+  output, _ = proc.communicate()
 
   if cwd:
     os.chdir(original_cwd)