No Escaping Leads to an HTTP 505

Today I stumbled over an HTTP 505 error (version not supported) for the very first time. After tracking the request with wireshark, all was clear. The TCP stream looked like this:

GET /search.do?textfield=Max Muster HTTP/1.1
Accept-Encoding: identity
Host: intranet.???.ch
User-Agent: Python-urllib/3.3
Connection: close

HTTP/1.1 505 HTTP Version Not Supported
Server: Apache-Coyote/1.1
Date: Thu, 06 Mar 2014 08:26:59 GMT
Connection: close

The space between Max and Muster gets the HTTP server disturbed because the second space on this line is supposed to indicate the beginning of the protocol definition. In python (v3.3) urllib.request.Request(url=target_url) does not escape the url. I have to do it by myself. So requesting GET /search.do?textfield=Max%20Muster HTTP/1.1 would be the correct way.