diff --git a/image/bin/my_init b/image/bin/my_init
index d48ac06..612c15b 100755
--- a/image/bin/my_init
+++ b/image/bin/my_init
@@ -96,7 +96,7 @@ def import_envvars(clear_existing_environment=True, override_existing_environmen
     if clear_existing_environment:
         os.environ.clear()
     for name, value in new_env.items():
-        if override_existing_environment or name not in os.environ:
+        if override_existing_environment or not name in os.environ:
             os.environ[name] = value
 
 
@@ -132,10 +132,11 @@ def shquote(s):
 def sanitize_shenvname(s):
     return re.sub(SHENV_NAME_WHITELIST_REGEX, "_", s)
 
-
 # Waits for the child process with the given PID, while at the same time
 # reaping any other child processes that have exited (e.g. adopted child
 # processes that have terminated).
+
+
 def waitpid_reap_other_children(pid):
     global terminated_child_processes
 
@@ -201,7 +202,7 @@ def run_command_killable(*argv):
     pid = os.spawnvp(os.P_NOWAIT, filename, argv)
     try:
         status = waitpid_reap_other_children(pid)
-    except BaseException:
+    except BaseException as s:
         warn("An error occurred. Aborting.")
         stop_child_process(filename, pid)
         raise
@@ -263,11 +264,8 @@ def run_startup_files():
 
 def start_runit():
     info("Booting runit daemon...")
-    pid = os.spawnl(os.P_NOWAIT,
-                    "/usr/bin/runsvdir",
-                    "/usr/bin/runsvdir",
-                    "-P",
-                    "/etc/service")
+    pid = os.spawnl(os.P_NOWAIT, "/usr/bin/runsvdir", "/usr/bin/runsvdir",
+                    "-P", "/etc/service")
     info("Runit started as PID %d" % pid)
     return pid
 
@@ -334,9 +332,7 @@ def main(args):
                     info("Runit exited with status %d" % exit_status)
         else:
             info("Running %s..." % " ".join(args.main_command))
-            pid = os.spawnvp(os.P_NOWAIT,
-                             args.main_command[0],
-                             args.main_command)
+            pid = os.spawnvp(os.P_NOWAIT, args.main_command[0], args.main_command)
             try:
                 exit_code = waitpid_reap_other_children(pid)
                 if exit_code is None:
@@ -348,7 +344,7 @@ def main(args):
             except KeyboardInterrupt:
                 stop_child_process(args.main_command[0], pid)
                 raise
-            except BaseException:
+            except BaseException as s:
                 warn("An error occurred. Aborting.")
                 stop_child_process(args.main_command[0], pid)
                 raise
@@ -360,50 +356,25 @@ def main(args):
                 stop_child_process("runit daemon", runit_pid)
             wait_for_runit_services()
 
-
 # Parse options.
 parser = argparse.ArgumentParser(description='Initialize the system.')
-parser.add_argument(
-    'main_command',
-    metavar='MAIN_COMMAND',
-    type=str,
-    nargs='*',
-    help='The main command to run. (default: runit)')
-parser.add_argument(
-    '--enable-insecure-key',
-    dest='enable_insecure_key',
-    action='store_const',
-    const=True,
-    default=False,
-    help='Install the insecure SSH key')
-parser.add_argument(
-    '--skip-startup-files',
-    dest='skip_startup_files',
-    action='store_const',
-    const=True,
-    default=False,
-    help='Skip running /etc/my_init.d/* and /etc/rc.local')
-parser.add_argument(
-    '--skip-runit',
-    dest='skip_runit',
-    action='store_const',
-    const=True,
-    default=False,
-    help='Do not run runit services')
-parser.add_argument(
-    '--no-kill-all-on-exit',
-    dest='kill_all_on_exit',
-    action='store_const',
-    const=False,
-    default=True,
-    help='Do not kill all processes on the system upon exiting')
-parser.add_argument(
-    '--quiet',
-    dest='log_level',
-    action='store_const',
-    const=LOG_LEVEL_WARN,
-    default=LOG_LEVEL_INFO,
-    help='Only print warnings and errors')
+parser.add_argument('main_command', metavar='MAIN_COMMAND', type=str, nargs='*',
+                    help='The main command to run. (default: runit)')
+parser.add_argument('--enable-insecure-key', dest='enable_insecure_key',
+                    action='store_const', const=True, default=False,
+                    help='Install the insecure SSH key')
+parser.add_argument('--skip-startup-files', dest='skip_startup_files',
+                    action='store_const', const=True, default=False,
+                    help='Skip running /etc/my_init.d/* and /etc/rc.local')
+parser.add_argument('--skip-runit', dest='skip_runit',
+                    action='store_const', const=True, default=False,
+                    help='Do not run runit services')
+parser.add_argument('--no-kill-all-on-exit', dest='kill_all_on_exit',
+                    action='store_const', const=False, default=True,
+                    help='Don\'t kill all processes on the system upon exiting')
+parser.add_argument('--quiet', dest='log_level',
+                    action='store_const', const=LOG_LEVEL_WARN, default=LOG_LEVEL_INFO,
+                    help='Only print warnings and errors')
 args = parser.parse_args()
 log_level = args.log_level
 
@@ -412,12 +383,9 @@ if args.skip_runit and len(args.main_command) == 0:
     sys.exit(1)
 
 # Run main function.
-signal.signal(signal.SIGTERM,
-              lambda signum, frame: ignore_signals_and_raise_keyboard_interrupt('SIGTERM'))
-signal.signal(signal.SIGINT,
-              lambda signum, frame: ignore_signals_and_raise_keyboard_interrupt('SIGINT'))
-signal.signal(signal.SIGALRM,
-              lambda signum, frame: raise_alarm_exception())
+signal.signal(signal.SIGTERM, lambda signum, frame: ignore_signals_and_raise_keyboard_interrupt('SIGTERM'))
+signal.signal(signal.SIGINT, lambda signum, frame: ignore_signals_and_raise_keyboard_interrupt('SIGINT'))
+signal.signal(signal.SIGALRM, lambda signum, frame: raise_alarm_exception())
 try:
     main(args)
 except KeyboardInterrupt: