code: function(d) {
      return d.dcEnd || (d.dcEnd =
        later.date.prev(
          later.Y.val(d),
          later.M.val(d),
          Math.min(later.dc.val(d) * 7, later.D.extent(d)[1])));
    }
docs: The last day of the month with the same day of week count as the date
  specified.
  
  @param {Date} d: The specified date