Integration code for CSS selectors using `Soup Sieve <https://facelessuser.github.io/soupsieve/>`_ (pypi: ``soupsieve``).
Acquire a `CSS` object through the `element.Tag.css` attribute of
the starting point of your CSS selector, or (if you want to run a
selector against the entire document) of the `BeautifulSoup` object
itself.
The main advantage of doing this instead of using ``soupsieve``
functions is that you don't need to keep passing the `element.Tag` to be
selected against, since the `CSS` object is permanently scoped to that
`element.Tag`.