diff --git a/docs/source/run.rst b/docs/source/run.rst
index cfc3ba37..3100c526 100644
--- a/docs/source/run.rst
+++ b/docs/source/run.rst
@@ -32,10 +32,10 @@ Example with the test app:
 
     def app(environ, start_response):
         """Simplest possible application object"""
-        data = 'Hello, World!\n'
+        data = b'Hello, World!\n'
         status = '200 OK'
         response_headers = [
-            ('Content-type','text/plain'),
+            ('Content-type', 'text/plain'),
             ('Content-Length', str(len(data)))
         ]
         start_response(status, response_headers)