<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def log_level(self, level):
 """Set maximum log `level` by setting matches for PRIORITY. """

        if 0 <= level <= 7:
            for i in range(level+1):
                self.add_match(PRIORITY="%d" % i)
        else:
            raise ValueError("Log level must be 0 <= level <= 7")