code: def _ensure_started(self):
          
          if self._process and self._process.poll() is None:
              return
  
          if not getattr(self, "_cmd"):
              raise RuntimeError("Player command is not configured")
  
          log.debug("Starting playback command: %r", self._cmd)
          self._process = SilentPopen(self._cmd)
          self._post_start()
docs: Ensure player backing process is started