# File lib/cancan/ability.rb, line 213
    def unauthorized_message(action, subject)
      keys = unauthorized_message_keys(action, subject)
      variables = {:action => action.to_s}
      variables[:subject] = (subject.class == Class ? subject : subject.class).to_s.underscore.humanize.downcase
      message = I18n.translate(nil, variables.merge(:scope => :unauthorized, :default => keys + [""]))
      message.blank? ? nil : message
    end