gistfile1.rb

 def email_notification

    <<-TEXT
    Hello, #{email_notification_params[:reader_name]}

You should return a book #{email_notification_params[:book_title]} authored by "#{email_notification_params[:book_author]}" in  #{email_notification_params[:time_left]} hours.

Otherwise you will be charged $#{email_notification_params[:penalty_per_hour]} per hour.
    TEXT

  end

  def email_notification_params

    {
        reader_name: reader_with_book.name,
        book_title: reader_with_book.book.title,
        book_author: reader_with_book.book.author.name,
        time_left: ((issue_datetime.to_i - Time.now.to_i) / 3600),
        penalty_per_hour: sprintf("%.2f", ((reader_with_book.book.penalty_per_hour) / 100)).to_f

    }

  end