code: public function calculate(Cell $pCell = null)
      {
          try {
              return $this->calculateCellValue($pCell);
          } catch (\Exception $e) {
              throw new Exception($e->getMessage());
          }
      }
docs: Calculate cell value (using formula from a cell ID)
  Retained for backward compatibility.
  
  @param Cell $pCell Cell to calculate
  
  @throws Exception
  
  @return mixed