如何允许用户从 rails 的多选框中选择零个选项？

class Person< ApplicationRecord
  validates :phone_numbers, allow_blank: true
end

<%= form_with(model: person) do |form| %>
  <%= form.collection_select :phone_numbers, PhoneNumber.all, :id, :number, {}, { multiple: true, include_blank: true } %>
  <%= form.submit %>
<% end %>

class PeopleController< ApplicationController
  def create
    person_params[:phone_numbers] = [] if person_params[:phone_numbers].blank?
    @person = Person.new(person_params)
    if @person.save
      redirect_to @person
    else
      render :new
    end
  end

  private

  def person_params
    params.require(:person).permit(:name, phone_numbers: [])
  end
end