[py3] Fixed a regression introduced in fcc8de05.

Thanks George Marshall for the report.

django/core/servers/basehttp.py

@@ -202,7 +202,7 @@ class WSGIRequestHandler(simple_server.WSGIRequestHandler, object):
 def run(addr, port, wsgi_handler, ipv6=False, threading=False):
     server_address = (addr, port)
     if threading:
-        httpd_cls = type('WSGIServer', (socketserver.ThreadingMixIn, WSGIServer), {})
+        httpd_cls = type(str('WSGIServer'), (socketserver.ThreadingMixIn, WSGIServer), {})
     else:
         httpd_cls = WSGIServer
     httpd = httpd_cls(server_address, WSGIRequestHandler, ipv6=ipv6)