thing.rb

module ErrorConversion
  def to_error
    Error.new(error: name, description: body)
  end
end

class Error
  attr_reader :error, :description

  def initialize(attributes)
    @error = attributes[:error]
    @description = attributes[:description]
  end
end

class Beep
  attr_reader :name, :body

  def initialize(attributes)
    @name = attributes[:name]
    @body = attributes[:body]
  end
end

beep = Beep.new(name: 'Bonk', body: 'Im bonkin')
beep.extend(ErrorConversion)
beep_error = beep.to_error
puts beep_error.error
puts beep_error.description