The BeautifulSoup class is oriented towards skipping over
common HTML errors like unclosed tags. However, sometimes it makes
errors of its own. For instance, consider this fragment:
<b>Foo<b>Bar</b></b>
This is perfectly valid (if bizarre) HTML. However, the
BeautifulSoup class will implicitly close the first b tag when it
encounters the second 'b'. It will think the author wrote
"<b>Foo<b>Bar", and didn't close the first 'b' tag, because
there's no real-world reason to bold something that's already
bold. When it encounters '</b></b>' it will close two more 'b'
tags, for a grand total of three tags closed instead of two. This
can throw off the rest of your document structure. The same is
true of a number of other tags, listed below.
It's much more common for someone to forget to close a 'b' tag
than to actually use nested 'b' tags, and the BeautifulSoup class
handles the common case. This class handles the not-co-common
case: where you can't believe someone wrote what they did, but
it's valid HTML and BeautifulSoup screwed up by assuming it
wouldn't be.
Definition at line 1604 of file BeautifulSoup.py.