def doc_children(self, doctype, limiters=[]):
        """Finds all grand-children of this element's docstrings that match
        the specified doctype. If 'limiters' is specified, only docstrings
        with those doctypes are searched.
        """
        result = []
        for doc in self.docstring:
            if len(limiters) == 0 or doc.doctype in limiters:
                result.extend(doc.children(doctype))

        return result