Returns an empty ``Document``.

        Arguments:

        - ``base_uri``: optional URL used as the basis when expanding
                               relative URLs in the document.
        - ``draft``: a ``Draft`` instance that selects the version of the spec
                     to which the document should conform. Defaults to
                     ``drafts.AUTO``.

def empty(cls, base_uri=None, draft=AUTO):
        """Returns an empty ``Document``.

        Arguments:

        - ``base_uri``: optional URL used as the basis when expanding
                               relative URLs in the document.
        - ``draft``: a ``Draft`` instance that selects the version of the spec
                     to which the document should conform. Defaults to
                     ``drafts.AUTO``.
        """
        return cls.from_object({}, base_uri=base_uri, draft=draft)