human
Solve the following python programming problem given the following code:
def AuthCASHandler(application, authority) : 
    '
    middleware to implement CAS 1.0 authentication

    There are several possible outcomes:

    0. If the REMOTE_USER environment variable is already populated;
       then this middleware is a no-op, and the request is passed along
       to the application.

    1. If a query argument \'ticket\' is found, then an attempt to
       validate said ticket /w the authentication service done.  If the
       ticket is not validated.
an 403 \'Forbidden\' exception is raised.
       Otherwise, the REMOTE_USER variable is set with the NetID that
       was validated and AUTH_TYPE is set to "cas".

    2. Otherwise, a 303 \'See Other\' is returned to the client directing
       them to login using the CAS service.  After logon, the service
       will send them back to this same URL, only with a \'ticket\' query
       argument.

    Parameters:

        ``authority``

            This is a fully-qualified URL to a CAS 1.0 service. The URL
            should end with a \'/\' and have the \'login\' and \'validate\'
            sub-paths as described in the CAS 1.0 documentation.

    ' 
    assert (authority.endswith ('/') and authority.startswith ('http')) 
    def cas_application(environ, start_response) : 
        username = environ.get ('REMOTE_USER', '') 
        if username : 
            return application (environ, start_response) 
qs = environ.get ('QUERY_STRING', '').split ('&') 
        if (qs and qs [(- 1)].startswith ('ticket=')) : 
            ticket = qs.pop ().split ('=', 1) [1] 
            environ ['QUERY_STRING'] = '&'.join (qs) 
            service = construct_url (environ) 
            args = urlencode ({ 
                'service' : service, 
                'ticket' : ticket, 
}) 
            requrl = ((authority + 'validate?') + args) 
            result = urlopen (requrl).read ().split ('
') 
            if ('yes' == result [0]) : 
                environ ['REMOTE_USER'] = result [1] 
                environ ['AUTH_TYPE'] = 'cas' 
         ...

    
    

    Fix the buggy line: return application
assistant
#Here is Python program to fix the buggy line: return application
.

return def cas_application(