(self, doc_id)
:param doc_id: ID of the doc
        :return: The doc with the given ID
:param doc_id: ID of the doc
        :return: The doc with the given ID
: param doc_id : ID of the doc : return : The doc with the given ID
def get_doc(self, doc_id):
        """
        :param doc_id: ID of the doc
        :return: The doc with the given ID
        """
        raise NotImplementedError
def get_doc ( self , doc_id ) : raise NotImplementedError