diff --git a/tools/thread_utils.py b/tools/thread_utils.py
index 5810332..e92d2c8 100755
--- a/tools/thread_utils.py
+++ b/tools/thread_utils.py
@@ -8,6 +8,7 @@
 from threading import Thread
 import traceback
 
+
 # A thread that is given a list of jobs. The thread will repeatedly take a job
 # from the list of jobs (which is shared with other threads) and execute it
 # until there is no more jobs.
@@ -21,99 +22,101 @@
 # setting an appropriate timeout).
 class WorkerThread(Thread):
 
-  # The initialization of a WorkerThread is never run concurrently with the
-  # initialization of other WorkerThreads.
-  def __init__(self, jobs, jobs_lock, stop_on_first_failure, worker_id):
-    Thread.__init__(self)
-    self.completed = False
-    self.jobs = jobs
-    self.jobs_lock = jobs_lock
-    self.number_of_jobs = len(jobs)
-    self.stop_on_first_failure = stop_on_first_failure
-    self.success = True
-    self.worker_id = worker_id
+    # The initialization of a WorkerThread is never run concurrently with the
+    # initialization of other WorkerThreads.
+    def __init__(self, jobs, jobs_lock, stop_on_first_failure, worker_id):
+        Thread.__init__(self)
+        self.completed = False
+        self.jobs = jobs
+        self.jobs_lock = jobs_lock
+        self.number_of_jobs = len(jobs)
+        self.stop_on_first_failure = stop_on_first_failure
+        self.success = True
+        self.worker_id = worker_id
 
-  def run(self):
-    print_thread("Starting worker", self.worker_id)
-    while True:
-      (job, job_id) = self.take_job(self.jobs, self.jobs_lock)
-      if job is None:
-        break
-      try:
-        print_thread(
-            "Starting job %s/%s" % (job_id, self.number_of_jobs),
-            self.worker_id)
-        exit_code = job(self.worker_id)
-        print_thread(
-            "Job %s finished with exit code %s"
-                % (job_id, exit_code),
-            self.worker_id)
-        if exit_code:
-          self.success = False
-          if self.stop_on_first_failure:
-            self.clear_jobs(self.jobs, self.jobs_lock)
-            break
-      except:
-        print_thread("Job %s crashed" % job_id, self.worker_id)
-        print_thread(traceback.format_exc(), self.worker_id)
-        self.success = False
-        if self.stop_on_first_failure:
-          self.clear_jobs(self.jobs, self.jobs_lock)
-          break
-    print_thread("Exiting", self.worker_id)
-    self.completed = True
+    def run(self):
+        print_thread("Starting worker", self.worker_id)
+        while True:
+            (job, job_id) = self.take_job(self.jobs, self.jobs_lock)
+            if job is None:
+                break
+            try:
+                print_thread(
+                    "Starting job %s/%s" % (job_id, self.number_of_jobs),
+                    self.worker_id)
+                exit_code = job(self.worker_id)
+                print_thread(
+                    "Job %s finished with exit code %s" % (job_id, exit_code),
+                    self.worker_id)
+                if exit_code:
+                    self.success = False
+                    if self.stop_on_first_failure:
+                        self.clear_jobs(self.jobs, self.jobs_lock)
+                        break
+            except:
+                print_thread("Job %s crashed" % job_id, self.worker_id)
+                print_thread(traceback.format_exc(), self.worker_id)
+                self.success = False
+                if self.stop_on_first_failure:
+                    self.clear_jobs(self.jobs, self.jobs_lock)
+                    break
+        print_thread("Exiting", self.worker_id)
+        self.completed = True
 
-  def take_job(self, jobs, jobs_lock):
-    jobs_lock.acquire()
-    job_id = self.number_of_jobs - len(jobs) + 1
-    job = jobs.pop(0) if jobs else None
-    jobs_lock.release()
-    return (job, job_id)
+    def take_job(self, jobs, jobs_lock):
+        jobs_lock.acquire()
+        job_id = self.number_of_jobs - len(jobs) + 1
+        job = jobs.pop(0) if jobs else None
+        jobs_lock.release()
+        return (job, job_id)
 
-  def clear_jobs(self, jobs, jobs_lock):
-    jobs_lock.acquire()
-    jobs.clear()
-    jobs_lock.release()
+    def clear_jobs(self, jobs, jobs_lock):
+        jobs_lock.acquire()
+        jobs.clear()
+        jobs_lock.release()
+
 
 def run_in_parallel(jobs, number_of_workers, stop_on_first_failure):
-  assert number_of_workers > 0
-  if number_of_workers > len(jobs):
-    number_of_workers = len(jobs)
-  if number_of_workers == 1:
-    return run_in_sequence(jobs, stop_on_first_failure)
-  jobs_lock = threading.Lock()
-  threads = []
-  for worker_id in range(1, number_of_workers + 1):
-    threads.append(
-        WorkerThread(jobs, jobs_lock, stop_on_first_failure, worker_id))
-  for thread in threads:
-    thread.start()
-  for thread in threads:
-    thread.join()
-  for thread in threads:
-    if not thread.completed or not thread.success:
-      return 1
-  return 0
+    assert number_of_workers > 0
+    if number_of_workers > len(jobs):
+        number_of_workers = len(jobs)
+    if number_of_workers == 1:
+        return run_in_sequence(jobs, stop_on_first_failure)
+    jobs_lock = threading.Lock()
+    threads = []
+    for worker_id in range(1, number_of_workers + 1):
+        threads.append(
+            WorkerThread(jobs, jobs_lock, stop_on_first_failure, worker_id))
+    for thread in threads:
+        thread.start()
+    for thread in threads:
+        thread.join()
+    for thread in threads:
+        if not thread.completed or not thread.success:
+            return 1
+    return 0
+
 
 def run_in_sequence(jobs, stop_on_first_failure):
-  combined_exit_code = 0
-  worker_id = None
-  for job in jobs:
-    try:
-      exit_code = job(worker_id)
-      if exit_code:
-        combined_exit_code = exit_code
-        if stop_on_first_failure:
-          break
-    except:
-      print(traceback.format_exc())
-      combined_exit_code = 1
-      if stop_on_first_failure:
-        break
-  return combined_exit_code
+    combined_exit_code = 0
+    worker_id = None
+    for job in jobs:
+        try:
+            exit_code = job(worker_id)
+            if exit_code:
+                combined_exit_code = exit_code
+                if stop_on_first_failure:
+                    break
+        except:
+            print(traceback.format_exc())
+            combined_exit_code = 1
+            if stop_on_first_failure:
+                break
+    return combined_exit_code
+
 
 def print_thread(msg, worker_id):
-  if worker_id is None:
-    print(msg)
-  else:
-    print('WORKER %s: %s' % (worker_id, msg))
\ No newline at end of file
+    if worker_id is None:
+        print(msg)
+    else:
+        print('WORKER %s: %s' % (worker_id, msg))