<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def warn(self, msg, *args, **kwargs):
 """Logs 'msg % args' with severity 'WARN'."""

    if six.PY3:
      warnings.warn("The 'warn' method is deprecated, use 'warning' instead",
                    DeprecationWarning, 2)
    self.log(logging.WARN, msg, *args, **kwargs)