def end_of_quarter(year, quarter)
      case quarter
      when QUARTER_1
        end_of_month(year, 3)
      when QUARTER_2
        end_of_month(year, 6)
      when QUARTER_3
        end_of_month(year, 9)
      when QUARTER_4
        end_of_month(year, 12)
      else
        raise "invalid quarter"
      end
    end
def end_of_quarter(year, quarter)
      case quarter
      when QUARTER_1
        end_of_month(year, 3)
      when QUARTER_2
        end_of_month(year, 6)
      when QUARTER_3
        end_of_month(year, 9)
      when QUARTER_4
        end_of_month(year, 12)
      else
        raise "invalid quarter"
      end
    end
Return the ending date for a particular quarter

 @param year [Integer] the retail year
 @param quarter [Integer] the quarter of the year, a number from 1 - 4
 @return [Date] the end date of the quarter