diff --git a/rtc_tools/testing/build_apprtc.py b/rtc_tools/testing/build_apprtc.py
index d601357459..2f680e6ad1 100755
--- a/rtc_tools/testing/build_apprtc.py
+++ b/rtc_tools/testing/build_apprtc.py
@@ -27,41 +27,41 @@ USAGE_STR = "Usage: {} <apprtc_dir> <go_dir> <output_dir>"
 
 
 def _ConfigureApprtcServerToDeveloperMode(app_yaml_path):
-    for line in fileinput.input(app_yaml_path, inplace=True):
-        # We can't click past these in browser-based tests, so disable them.
-        line = line.replace('BYPASS_JOIN_CONFIRMATION: false',
-                            'BYPASS_JOIN_CONFIRMATION: true')
-        sys.stdout.write(line)
+  for line in fileinput.input(app_yaml_path, inplace=True):
+    # We can't click past these in browser-based tests, so disable them.
+    line = line.replace('BYPASS_JOIN_CONFIRMATION: false',
+                        'BYPASS_JOIN_CONFIRMATION: true')
+    sys.stdout.write(line)
 
 
 def main(argv):
-    if len(argv) != 4:
-        return USAGE_STR.format(argv[0])
+  if len(argv) != 4:
+    print(USAGE_STR.format(argv[0]))
 
-    apprtc_dir = os.path.abspath(argv[1])
-    go_root_dir = os.path.abspath(argv[2])
-    golang_workspace = os.path.abspath(argv[3])
+  apprtc_dir = os.path.abspath(argv[1])
+  go_root_dir = os.path.abspath(argv[2])
+  golang_workspace = os.path.abspath(argv[3])
 
-    app_yaml_path = os.path.join(apprtc_dir, 'out', 'app_engine', 'app.yaml')
-    _ConfigureApprtcServerToDeveloperMode(app_yaml_path)
+  app_yaml_path = os.path.join(apprtc_dir, 'out', 'app_engine', 'app.yaml')
+  _ConfigureApprtcServerToDeveloperMode(app_yaml_path)
 
-    utils.RemoveDirectory(golang_workspace)
+  utils.RemoveDirectory(golang_workspace)
 
-    collider_dir = os.path.join(apprtc_dir, 'src', 'collider')
-    shutil.copytree(collider_dir, os.path.join(golang_workspace, 'src'))
+  collider_dir = os.path.join(apprtc_dir, 'src', 'collider')
+  shutil.copytree(collider_dir, os.path.join(golang_workspace, 'src'))
 
-    golang_path = os.path.join(go_root_dir, 'bin',
-                               'go' + utils.GetExecutableExtension())
-    golang_env = os.environ.copy()
-    golang_env['GOROOT'] = go_root_dir
-    golang_env['GOPATH'] = golang_workspace
-    golang_env['GO111MODULE'] = 'off'
-    collider_out = os.path.join(
-        golang_workspace, 'collidermain' + utils.GetExecutableExtension())
-    subprocess.check_call(
-        [golang_path, 'build', '-o', collider_out, 'collidermain'],
-        env=golang_env)
+  golang_path = os.path.join(go_root_dir, 'bin',
+                             'go' + utils.GetExecutableExtension())
+  golang_env = os.environ.copy()
+  golang_env['GOROOT'] = go_root_dir
+  golang_env['GOPATH'] = golang_workspace
+  golang_env['GO111MODULE'] = 'off'
+  collider_out = os.path.join(golang_workspace,
+                              'collidermain' + utils.GetExecutableExtension())
+  subprocess.check_call(
+      [golang_path, 'build', '-o', collider_out, 'collidermain'],
+      env=golang_env)
 
 
 if __name__ == '__main__':
-    sys.exit(main(sys.argv))
+  sys.exit(main(sys.argv))