There's no validate method as almost anything is a valid URL. There are some punctuation rules for splitting it up. Without any punctuation, you still have a valid URL.
Depending on the situation, we use following methods.
If you trust the data, and just want to verify if the protocol is HTTP, then urlparse is perfect.
If you want to make the URL is actually a true URL, use the cumbersome and maniacal regex
If you want to make sure it's a real web address, use the following code
import urllib try: urllib.urlopen(url) except IOError: print "Not a real URL"