<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def fetchallfirstvalues(self, sql: str, *args) -> List[Any]: """Executes SQL; returns list of first values of each row."""

        rows = self.fetchall(sql, *args)
        return [row[0] for row in rows]