code: function(d) {
      return d.wmExtent || (d.wmExtent = [1,
        (later.D.extent(d)[1] + (later.dw.val(later.M.start(d)) - 1) +
        (7 - later.dw.val(later.M.end(d)))) / 7]);
    }
docs: The minimum and maximum valid week of month values for the month indicated.
  Zero indicates the last week in the month.
  
  @param {Date} d: The date indicating the month to find values for