def get(self, id, pk='id', deleted=False):
        try:
            if pk == 'id':
                id = int(id)
            if deleted:
                spec = {pk: id}
            else:
                spec = {pk: id, 'data': {'$exists': 1}}
            fields = {'_id': 0}
            row = self.db.docs.find_one(spec, fields)
        except Exception as e:
            raise DatabaseException(e)
        if row:
            return Document(**row)
        raise NotFoundError('%s %s not found' % (pk, id))
def toggle_comment(self):
        "Toggle the selected comment tree between visible and hidden"

        current_index = self.nav.absolute_index
        self.content.toggle(current_index)

        # This logic handles a display edge case after a comment toggle. We
        # want to make sure that when we re-draw the page, the cursor stays at
        # its current absolute position on the screen. In order to do this,
        # apply a fixed offset if, while inverted, we either try to hide the
        # bottom comment or toggle any of the middle comments.
        if self.nav.inverted:
            data = self.content.get(current_index)
            if data['hidden'] or self.nav.cursor_index != 0:
                window = self._subwindows[-1][0]
                n_rows, _ = window.getmaxyx()
                self.nav.flip(len(self._subwindows) - 1)
                self.nav.top_item_height = n_rows