def until(time, &block)
      time = time.to_time if time.is_a?(::Date)
      @until = time
      return call_chain(block) if block_given?
      self
    end
def until(time, &block)
      time = time.to_time if time.is_a?(::Date)
      @until = time
      return call_chain(block) if block_given?
      self
    end
Used togeter with #each and other iteration methods to specify end of interation.