gistfile1.rb

class RiskFree

....

    def get_date(date)
      date = orig_date = date.to_date
      year = date.year
      data = fetch(year)
      result  = nil
      counter = 0
      while(!result)
        result = data[date]
        date-=1 #1 day before
        counter+=1
        # more than 1 month or out of current year
        break if (counter > 30 || date < orig_date.beginning_of_year)
      end
      return result if result
      date = (orig_date - 1.year).end_of_year
      RiskFree.new.get_date(date)
    end

....
end