HTMLParser.handle_starttag(tag, attrs)
This method is called to handle the start of a tag (e.g. <div id="main">).
The tag argument is the name of the tag converted to lower case. The attrs argument is a list of (name, value) pairs containing the attributes found inside the tag’s <> brackets. The name will be translated to lower case, and quotes in the value have been removed, and character and entity references have been replaced.
For instance, for the tag <A HREF="https://www