HTML tags that have a attribute name starting with a comma character aren't parsed and break future calls to feed(). 

The problem occurs when such attribute is the second one or later in the HTML tag. Doesn't seems to affect when it's the first attribute.

#POC:

from html.parser import HTMLParser

class MyHTMLParser(HTMLParser):
    def handle_starttag(self, tag, attrs):
        print("Encountered a start tag:", tag)

parser = MyHTMLParser()

#This is ok
parser.feed('<yyy id="poc" a,="">')

#This breaks
parser.feed('<zzz id="poc" ,a="">')

#Future calls to feed() will not work
parser.feed('<img id="poc" src=x>')