code: function(oColumn, iLevel) {
  			var vHeaderSpans = oColumn.getHeaderSpan();
  			var iHeaderSpan;
  
  			if (!vHeaderSpans) {
  				return 1;
  			}
  
  			if (!Array.isArray(vHeaderSpans)) {
  				vHeaderSpans = (vHeaderSpans + "").split(",");
  			}
  
  			function getSpan(sSpan) {
  				var result = parseInt(sSpan);
  				return isNaN(result) ? 1 : result;
  			}
  
  			if (isNaN(iLevel)) { // find max value of all spans in the header
  				iHeaderSpan = Math.max.apply(null, vHeaderSpans.map(getSpan));
  			} else {
  				iHeaderSpan = getSpan(vHeaderSpans[iLevel]);
  			}
  
  			return Math.max(iHeaderSpan, 1);
  		}
docs: Returns the header span of a given column. If <code>iLevel</code> is provided, the header span of that
  header row is returned if there is any defined, otherwise the maximum header span is returned.
  If there is no header span for the level, 1 is returned as a default value.
  
  @param {sap.ui.table.Column} oColumn Column of which the header span shall be returned.
  @param {int} [iLevel=0] Zero-based index of the header span for multi-labels.
  @returns {int} Header span.