code: public function _savePps(&$raList)
      {
          // Save each PPS WK
          $iC = count($raList);
          for ($i = 0; $i < $iC; ++$i) {
              fwrite($this->fileHandle, $raList[$i]->_getPpsWk());
          }
          // Adjust for Block
          $iCnt = count($raList);
          $iBCnt = $this->bigBlockSize / OLE::OLE_PPS_SIZE;
          if ($iCnt % $iBCnt) {
              fwrite($this->fileHandle, str_repeat("\x00", ($iBCnt - ($iCnt % $iBCnt)) * OLE::OLE_PPS_SIZE));
          }
      }
docs: Saves all the PPS's WKs.
  
  @param array $raList Reference to an array with all PPS's