module ActiveRecord::LegacyYamlAdapter::Rails420

def self.convert(klass, coder)
  attribute_set = coder["attributes"]
  klass.attribute_names.each do |attr_name|
    attribute = attribute_set[attr_name]
    if attribute.type.is_a?(Delegator)
      type_from_klass = klass.type_for_attribute(attr_name)
      attribute_set[attr_name] = attribute.with_type(type_from_klass)
    end
  end
  coder
end