code: def send_signal(self, s):
          
          self._get_signal_event(s)  # Check if signal has been enabled
          pid = self.get_pid()
          if not pid:
              raise ValueError('Daemon is not running.')
          os.kill(pid, s)
docs: Send a signal to the daemon process.
  
          The signal must have been enabled using the ``signals``
          parameter of :py:meth:`Service.__init__`. Otherwise, a
          ``ValueError`` is raised.