尝试使用批处理方法删除多路径firestore字段文档

我正在尝试删除具有多路径位置的字段文档 Firestore批处理方法。我以前是用实时数据库的更新方法来做的。现在我真的不知道怎么在消防站做。

deleteVenueFromEvent(event) 
{
var eventkey       = event.$key;
var venuekey       = event.venue.venuekey;

var batch          = this.afs.firestore.batch();

var eventRef       = this.eventCollection.doc(eventkey).ref;    
batch.update(eventRef, { venue: null });

var deleteVenueRef = this.venueCollection.doc(venuekey).collection('events').doc(eventkey).ref;
batch.delete(deleteVenueRef);  

batch.commit().then(function() {console.log('Batch Delete')});
}