ActiveAdmin has_many nested form

gistfile1.rb

form(:html => { :multipart => true }) do |f|
    f.inputs 'Main name' do
      f.input :name
    end

    f.inputs "Other sub-piece" do
      f.input :other_field_from_main_thing
      
      f.has_many :other_things do |thing|
        thing.inputs "things" do
          thing.input :thing_1 
          thing.input :thing_2
        end
      end
    end
    f.buttons
  end