Automating Chromecast to play Spotify/Pandora

I’m working on a project where I use Home Assistant’s REST API to send post request to trigger actions on my IoT devices. I have successfully sent local files and text to play on the Chromecast with this method, but have yet to get Pandora stations or Spotify playlists to be sent (which is ultimately my goal). Do any of you know a simplistic way to achieve this?

I don’t have Premium on Pandora so I’m not sure if Playlist will have its station id. If it does, you could use mkchromecast to cast Pandora to Chromecast audio. I just posted this method yesterday.