Mongoose populate with array of objects containing ref

I found the answer: populate('lists.list') works. Thanks to this question: Mongoose populate within an object?

lists: [
   {
      list: {
          type: Schema.ObjectId,
          require: true,
          ref: "List"
      },
      allocations: [
          {
              type: Number,
              required: true
          }
      ]
   }
],

=> Because it's an array of objects, you can do this -: Portfolio.populate('lists.list');

2.

lists: [
    {
        type: Schema.ObjectId,
        require: true,
        ref: "List"
    }
]

=> Because it's an array, you just have to do this -: Portfolio.populate('lists');