[twill] twill with threads

[Macarse]

Hi, I am doing a script that:
- Gets a list of ips
- Sets a threadpool
- With twill it logins to the http
- with urlib2 gets some html

The code that it's run in the threads looks like this:

def checkIP(ip):
    global results, resultsLock
    ret = False

    req = urllib2.Request( ip )
    try:
        response = urllib2.urlopen(req)
        homePage = response.read()

        #login
        go(ip + '/login.asp')
        fv('1', 'user', 'user')
        fv('1', 'password', 'password')
        submit('3')

        req = urllib2.Request(ip + '/status.asp')
        response = urllib2.urlopen(req)
        statusPage = response.read()

        resultsLock.acquire()
        results.write(ip)
        resultsLock.release()

    except URLError, e:
        ret = False
    except BadStatusLine, e:
        ret = False

    return ret


my question is: Is ok to use twill like that?
Is it thread safe?

Thanks for reading!