Stop the daemon.

def stop(self):
        """Stop the daemon."""
        if self.pidfile is None:
            raise DaemonError('Cannot stop daemon without PID file')

        pid = self._read_pidfile()
        if pid is None:
            # I don't think this should be a fatal error
            self._emit_warning('{prog} is not running'.format(prog=self.prog))
            return

        self._emit_message('Stopping {prog} ... '.format(prog=self.prog))

        try:
            # Try to terminate the process
            os.kill(pid, signal.SIGTERM)
        except OSError as ex:
            self._emit_failed()
            self._emit_error(str(ex))
            sys.exit(1)

        if self._pid_is_alive(pid, timeout=self.stop_timeout):
            # The process didn't terminate for some reason
            self._emit_failed()
            self._emit_error('Timed out while waiting for process (PID {pid}) '
                             'to terminate'.format(pid=pid))
            sys.exit(1)

        self._emit_ok()