test.rb

module Central
  module Interactors
    module ListWaitingQueue
      extend self

      def call()
        puts "Hello"
      end

      private
      class B
        attr_reader :b

        def initialize(b)
          @b = b
        end

        private
        class C
          attr_reader :c

        end
      end

      def i_am_hidden()

      end
    end
  end
end

puts Central::Interactors::ListWaitingQueue::B.new(12)
puts Central::Interactors::ListWaitingQueue::B::C.new
Central::Interactors::ListWaitingQueue.i_am_hidden