'Commit all dirtied parsed objects to the filesystem and write out the e-book file at outpath.
:param output: The path to write the saved e-book file to. If None, the path of the original book file is used.
:param keep_parsed: If True the parsed representations of committed items are kept in the cache.'

def commit(self, outpath=None, keep_parsed=False):

    for name in tuple(self.dirtied):
        self.commit_item(name, keep_parsed=keep_parsed)
