Added one tip to use this pattern in Python3.

docs/patterns/methodoverrides.rst

@@ -29,7 +29,7 @@ This can easily be accomplished with an HTTP middleware::
         def __call__(self, environ, start_response):
             method = environ.get('HTTP_X_HTTP_METHOD_OVERRIDE', '').upper()
             if method in self.allowed_methods:
-                method = method.encode('ascii', 'replace')
+                method = method.encode('ascii', 'replace')# Remove this line if you are using Python3. 
                 environ['REQUEST_METHOD'] = method
             if method in self.bodyless_methods:
                 environ['CONTENT_LENGTH'] = '0'