<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def raw_sql(self, query, results=False):
 """ Execute a given query string. Could have unexpected results if the query modifies the behavior of the session in a way unknown to Ibis; be careful. Parameters query : string DML or DDL statement results : boolean, default False Pass True if the query as a result set Returns ------- cur : ImpalaCursor if results=True, None otherwise You must call cur.release() after you are finished using the cursor. """

        return self._execute(query, results=results)