def drop_seconds

      h = @h.dup
      h.delete(:sec)
      h[:min] = 0 if h.empty?

      self.class.allocate.init(nil, { literal: true }, h)
    end
def drop_seconds

      h = @h.dup
      h.delete(:sec)
      h[:min] = 0 if h.empty?

      self.class.allocate.init(nil, { literal: true }, h)
    end
Returns a copy of this duration, omitting its seconds.