dilbert.py

import urllib.request
from html.parser import HTMLParser

class DilbertParser(HTMLParser):
    def handle_starttag(self, tag, attrs):
        if tag == "img":
            comic = False
            src = None
            for attr in attrs:
                name, value = attr
                if name == "class" and "img-comic" in value:
                    comic = True
                elif name == "src":
                    src = value 
            if comic:
                print("Dilbert comic image: %s" % src)

with urllib.request.urlopen('http://dilbert.com') as f:
    parser = DilbertParser()
    parser.feed(str(f.read()))