Mongodb - script collection multiples query

script.js

var conn = new Mongo();
var db = conn.getDB("test"); 


var myCursor = db.images.find();

myCursor.forEach( 
  function(myDoc) { 
    // print( "images: " + tojson(myDoc) ); 
    var myAlbum = db.albums.findOne( { "images": myDoc._id } );
    // print(myAlbum); 
    
    if (myAlbum == null) {
      print('images removed _id: ' + myDoc._id );
      db.images.remove(myDoc);
    }

  } 
);