class Shoulda::Matchers::ActiveModel::ValidateUniquenessOfMatcher

def set_scoped_attributes
  if @options[:scopes].present?
    @options[:scopes].all? do |scope|
      setter = :"#{scope}="
      if @subject.respond_to?(setter)
        @subject.send(setter, existing.send(scope))
        true
      else
        @failure_message = "#{class_name} doesn't seem to have a #{scope} attribute."
        false
      end
    end
  else
    true
  end
end