module HTTParty::ModuleInheritableAttributes::ClassMethods

def inherited(subclass)
  super
  @mattr_inheritable_attrs.each do |inheritable_attribute|
    ivar = :"@#{inheritable_attribute}"
    subclass.instance_variable_set(ivar, instance_variable_get(ivar).clone)
    if instance_variable_get(ivar).respond_to?(:merge)
      method = <<-EOM
        def self.#{inheritable_attribute}
          duplicate = ModuleInheritableAttributes.hash_deep_dup(#{ivar})
          #{ivar} = superclass.#{inheritable_attribute}.merge(duplicate)
        end
      EOM
      subclass.class_eval method
    end
  end
end