You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: classes.rb
    path of file: ./repos/artichoke/artichoke-backend/vendor/ruby/spec/ruby/core/array/fixtures
    
    the code of the file until where you have to start completion: class Object
  # This helper is defined here rather than in MSpec because
  # it is only used in #pack specs.
  def pack_format(count=nil, repeat=nil)
    format = instance_variable_get(:@
    
    def <=>(other); 0; end
    def ==(other); true; end
  end

  class UFOSceptic
    def <=>(other); raise "N-uh, UFO:s do not exist!"; end
  end

  class MockForCompared
    @@count = 0
    @@compared = false
    def initialize
      @@compared = false
      @order = (@@count += 1)
    end
    def <=>(rhs)
      @@compared = true
      return rhs.order <=> self.order
    end
    def self.compared?
      @@compared
    end

    protected
    attr_accessor :order
  end