Python -- CRLF injection via the host part of the url passed to urlopen()

Python reports:

An issue was discovered in urllib2 in Python 2.x through 2.7.17 and urllib in Python 3.x
through 3.8.0. CRLF injection is possible if the attacker controls a url parameter, as
demonstrated by the first argument to urllib.request.urlopen with \r\n (specifically in
the host component of a URL) followed by an HTTP header.