code: public function protectCells($pRange, $pPassword, $pAlreadyHashed = false)
      {
          // Uppercase coordinate
          $pRange = strtoupper($pRange);
  
          if (!$pAlreadyHashed) {
              $pPassword = Shared\PasswordHasher::hashPassword($pPassword);
          }
          $this->protectedCells[$pRange] = $pPassword;
  
          return $this;
      }
docs: Set protection on a cell range.
  
  @param string $pRange Cell (e.g. A1) or cell range (e.g. A1:E1)
  @param string $pPassword Password to unlock the protection
  @param bool $pAlreadyHashed If the password has already been hashed, set this to true
  
  @return Worksheet