I have an attribute (which is a function) and use a specific serializer using Active Model Serializers

I have the following Active Model Serializer and would like to use a specific serializer for a method called notes which is returning an array of notes from the instance.

I have tried this and some other variations:

class MenuNotesSerializer < ActiveModel::Serializer
  attributes :id, :name, :notes(NoteSerializer)

and:

class MenuNotesSerializer < ActiveModel::Serializer
  attributes :id, :name, :tns

  def tns
    object.notes  #  works , serializer: NoteSerializer
  end

  def tns
    object.notes, serializer: NoteSerializer #doesn't work
  end

Basically I have a NoteSerializer that I'd like to be used for the array returned by the notes method on menu. How can I achieve this?

class MenuNotesSerializer < ActiveModel::Serializer
  attributes :id, :name
  has_many :notes, serializer: NoteSerializer
end