code: function(row, tmpRowDepth) {
                  tmpRowDepth = tmpRowDepth || 1;
  
                  for(var n=0; n<row.length; n++) {
                      var col = row[n];
                      // Column has children, so keep counting
                      if(YAHOO.lang.isArray(col.children)) {
                          tmpRowDepth++;
                          countMaxRowDepth(col.children, tmpRowDepth);
                          tmpRowDepth--;
                      }
                      // No children, is it the max depth?
                      else {
                          if(tmpRowDepth > maxRowDepth) {
                              maxRowDepth = tmpRowDepth;
                          }
                      }
  
                  }
              }
docs: Calculate the max depth of descendants for this row