For void elements such as (<link>, <img>), there doesn't need to have xhtml empty end tag. HtmlParser which relies on the XHTML empty end syntax failed to handle this situation. 

from HTMLParser import HTMLParser

# create a subclass and override the handler methods
class MyHTMLParser(HTMLParser):
    def handle_starttag(self, tag, attrs):
        print "Encountered a start tag:", tag
    def handle_endtag(self, tag):
        print "Encountered an end tag :", tag
    def handle_data(self, data):
        print "Encountered some data  :", data

>>> parser.feed('<link rel="import"><img src="som">')
Encountered a start tag: link
Encountered a start tag: img
>>> parser.feed('<link rel="import"/><img src="som"/>')
Encountered a start tag: link
Encountered an end tag : link
Encountered a start tag: img
Encountered an end tag : img


Reference:
https://github.com/python/cpython/blob/bdfb14c688b873567d179881fc5bb67363a6074c/Lib/html/parser.py
http://www.w3.org/TR/html5/syntax.html#void-elements