def classes_for_day(day)
      classes = Tableau::ClassArray.new

      @modules.each do |mod|
        cfd = mod.classes_for_day(day)
        cfd.each { |cl| classes << cl } if cfd
      end

      classes.count > 0 ? classes : nil
    end
def classes_for_day(day)
      classes = Tableau::ClassArray.new

      @modules.each do |mod|
        cfd = mod.classes_for_day(day)
        cfd.each { |cl| classes << cl } if cfd
      end

      classes.count > 0 ? classes : nil
    end
Returns an array of the given day's classes