# File lib/date.rb, line 1105
  def self.valid_time? (h, min, s)
    h   += 24 if h   < 0
    min += 60 if min < 0
    s   += 60 if s   < 0
    return unless (0..24) === h and
                  (0..59) === min and
                  (0..59) === s
    time_to_day_fraction(h, min, s)
  end