code: function(year, ord) {
          var m = (ord + this.firstMonth - 2 * this.minMonth) %
              this.monthsInYear(year) + this.minMonth;
          this._validate(year, m, this.minDay,
              _exports.local.invalidMonth || _exports.regionalOptions[''].invalidMonth);
          return m;
      }
docs: Calculate actual month from ordinal position, starting from minMonth.
  @memberof BaseCalendar
  @param year {number} The year to examine.
  @param ord {number} The month's ordinal position.
  @return {number} The month's number.
  @throws Error if an invalid year/month.