code: public function setBreak($pCoordinate, $pBreak)
      {
          // Uppercase coordinate
          $pCoordinate = strtoupper($pCoordinate);
  
          if ($pCoordinate != '') {
              if ($pBreak == self::BREAK_NONE) {
                  if (isset($this->breaks[$pCoordinate])) {
                      unset($this->breaks[$pCoordinate]);
                  }
              } else {
                  $this->breaks[$pCoordinate] = $pBreak;
              }
          } else {
              throw new Exception('No cell coordinate specified.');
          }
  
          return $this;
      }
docs: Set break on a cell.
  
  @param string $pCoordinate Cell coordinate (e.g. A1)
  @param int $pBreak Break type (type of Worksheet::BREAK_*)
  
  @throws Exception
  
  @return Worksheet