How to export a CSV file with a header using python 2.7

I'm trying to figure out how to export the results of my script to a CSV file with python 2.7. The CSV file should contain two columns:

The first column should contain the URL results and I would like to give this column a name. The second column should contain the print result keyword found or keyword NOT found (as seen after the first and second print function in my code). I would like to name the second column as well.

My code:

import urllib2keyword = ['viewport']with open('top1m-edited.csv') as f:    for line in f:        strdomain = line.strip()        if '.nl' in strdomain:            try:                req = urllib2.Request(strdomain.strip())                response = urllib2.urlopen(req)                html_content = response.read()                for searchstring in keyword:                    if searchstring.lower() in str(html_content).lower():                        print (strdomain, keyword, 'keyword found')                    else:                        print (strdomain, 'keyword NOT found')            except urllib2.HTTPError:                print (strdomain,'HTTP ERROR')            except urllib2.URLError:                print (strdomain,'URL ERROR')            except urllib2.socket.error:                print (strdomain,'SOCKET ERROR')            except urllib2.ssl.CertificateError:                print (strdomain,'SSL Certificate ERROR')f.close()

So what kind of code do I need to add in order to achieve my goal?