多个fields_for在活动管理轨道中无法正常工作4

Question

我在主动管理员中创建了一个表单但是field_for for没有显示多个嵌套属性。

这是我的代码：

ActiveAdmin.register Application do
    actions :all, :except => [:destroy]

    permit_params :agent_code, :operator_id,
                    customer_attributes: [:email, person_attributes:[:name, :title_type, :first_name, :middle_name, 
                        :last_name, :id_type, :id_number, :birthday, :home_phone, :mobile_phone, :work_phone], next_of_kin_attributes:
                        [:first_name, :last_name, :home_phone]]

    form do |f|

      f.inputs "Your Details" do
        f.input :agent_code
        f.input :operator_id, as: :select, prompt: "Operator", collection: Operator.all
        f.fields_for :customer do |customer|
            customer.fields_for :person do |person|
                person.input :name, as: :hidden
                person.input :title_type, as: :select, prompt: "Title", class: 'selectpicker', collection: Person::TITLE_TYPES.map{|title_type| [ title_type[1], title_type[0] ]}
                person.input :first_name
                person.input :middle_name
                person.input :last_name
                person.select :id_type, as: :select, collection: Person::ID_TYPES.map{|id_type| [ id_type[1], id_type[0] ]} , prompt: 'ID Type', class: 'id_select_box'
                person.input :id_number
                person.input :birthday
                person.input :home_phone
                person.input :mobile_phone
                person.input :work_phone

            end
            customer.input :email
            customer.fields_for :next_of_kin do |next_of_kin|
                next_of_kin.input :first_name
                next_of_kin.input :last_name
                next_of_kin.input :home_phone
            end
        end
      end
      f.actions
    end  
end

在上面的代码中，当我编写Person属性时，它在前端是可见的，但是当我写下next_of_kin_attributes时，后者显示但前者不是。所以基本上我需要弄清楚我们如何在活动管理中执行多级嵌套属性。

如果我在两个字段之间写了customer_attributes attributes(:email)，则它不会显示两个fields_for属性中的任何一个。

提前致谢！