code: public function unprotectCells($pRange)
      {
          // Uppercase coordinate
          $pRange = strtoupper($pRange);
  
          if (isset($this->protectedCells[$pRange])) {
              unset($this->protectedCells[$pRange]);
          } else {
              throw new Exception('Cell range ' . $pRange . ' not known as protected.');
          }
  
          return $this;
      }
docs: Remove protection on a cell range.
  
  @param string $pRange Cell (e.g. A1) or cell range (e.g. A1:E1)
  
  @throws Exception
  
  @return Worksheet