'Extract revisions and save for next call.'

def save_data(self, storage, data):

    revs = self.extract_data(data)
    is_all = (len(revs) < self.revisions)
    data = {u'revisions': revs, u'is_all': is_all}
    storage.save_document_history(self.locale, self.slug, data)
    requested_revisions = revs[:self.revisions]
    requested_revisions.reverse()
    return requested_revisions
