Test if Sonos.snapshot has a snapshot

I’ve got a Zigbee Smart Knob that I want to mount outside. The behaviour I want is:

  1. If the Sonos is playing something, take a snapshot and then pause the music when the button is pressed.
  2. If the Sonos (O-Pool) is not playing anything then play something (I’m defaulting to PopRocks on XM) when the button is pressed UNLESS there is a snapshot, then resume the snapshot.
  3. Volume up and down should respond to turning the knob.

Everything above is working except resuming the snapshot. How do I know if there is a snapshot saved?

alias: O_SmartKnob Volume
description: ""
trigger:
  - device_id: 113e1441be41fea5c6c704fbac64ef33
    domain: zha
    platform: device
    type: device_rotated_slow
    subtype: right
    id: VolUpSlow
  - device_id: 113e1441be41fea5c6c704fbac64ef33
    domain: zha
    platform: device
    type: device_rotated_slow
    subtype: left
    id: VolDownSlow
  - device_id: 113e1441be41fea5c6c704fbac64ef33
    domain: zha
    platform: device
    type: remote_button_short_press
    subtype: button
    id: VolReport
condition: []
action:
  - choose:
      - conditions:
          - condition: trigger
            id: VolUpSlow
        sequence:
          - service: media_player.volume_up
            data: {}
            target:
              device_id: 7cb8206605453577ff2d0593925dee3d
          - service: media_player.volume_up
            data: {}
            target:
              device_id:
                - fba266a21cc44ffbe54b21040155cf2c
      - conditions:
          - condition: trigger
            id: VolDownSlow
        sequence:
          - service: media_player.volume_down
            data: {}
            target:
              device_id: 7cb8206605453577ff2d0593925dee3d
          - service: media_player.volume_down
            data: {}
            target:
              device_id: fba266a21cc44ffbe54b21040155cf2c
      - conditions:
          - condition: trigger
            id: VolReport
          - condition: device
            device_id: fba266a21cc44ffbe54b21040155cf2c
            domain: media_player
            entity_id: media_player.o_pool
            type: is_paused
        sequence:
          - service: media_player.play_media
            target:
              entity_id: media_player.o_pool
            data:
              media_content_id: FV:2/61
              media_content_type: favorite_item_id
            metadata:
              title: 17 - PopRocks
              thumbnail: >-
                http://pri.art.prod.streaming.siriusxm.com/images/channel/20180725/9450-1-17-00-320x320.png
              media_class: genre
              children_media_class: null
              navigateIds:
                - {}
                - media_content_type: favorites
                  media_content_id: ""
                - media_content_type: favorites_folder
                  media_content_id: object.item.audioItem.audioBroadcast
      - conditions:
          - condition: trigger
            id: VolReport
          - condition: device
            device_id: fba266a21cc44ffbe54b21040155cf2c
            domain: media_player
            entity_id: media_player.o_pool
            type: is_playing
        sequence:
          - service: sonos.snapshot
            data:
              with_group: true
              entity_id: media_player.o_pool
          - service: media_player.media_pause
            data: {}
            target:
              entity_id: media_player.o_pool
mode: single