module Sandbox

def self.add_attributes(klass, *attrs)
  self.const_get_from_string(klass).class_eval do
    attr_accessor *attrs
    # set up the 'initialize' method to assign the attributes
    define_method(:initialize) do |*value_hash|
      value_hash = value_hash.first
      value_hash ||= {}
      value_hash.each do |k, v|
        instance_variable_set("@#{k.to_s}", v)
      end
    end
  end
end