Immutable complete struct

immutable_complete.rb

$ Person = Struct.new(:first_name, :last_name) do
    def initialize(*args)
      raise ArgumentError, "Incorrect arguments" unless args[0].member?(:first_name) && args[0].member?(:last_name)
      super(*args)
      self.freeze
    end
  end
=> Person

$ eryan = Person.new(first_name: "Eryan")
=> ArgumentError (Incorrect arguments)

$ eryan = Person.new(first_name: "Eryan", bad_argument: "Cobham")
=> ArgumentError (Incorrect arguments)

$ eryan = Person.new(first_name: "Eryan", last_name: "Cobham")
=> #<struct Person first_name="Eryan", last_name="Cobham">