Class level privates

hello.rb

class Hello
  def self.first
    puts "Boo!"
  end

  private
  def self.second
    puts "Buh!"
  end

  class << self
    def third
      puts "Bugger"
    end
  end
end

Hello.first
Hello.second
Hello.third

-> "Boo!"
-> "Buh!"
-> "Bugger"