code: public function create()
  	{
  		if ($GLOBALS['TL_DCA'][$this->strTable]['config']['notCreatable'])
  		{
  			throw new InternalServerErrorException('Table "' . $this->strTable . '" is not creatable.');
  		}
  
  		$this->import(Files::class, 'Files');
  		$strFolder = Input::get('pid', true);
  
  		if ($strFolder == '' || !file_exists($this->strRootDir . '/' . $strFolder) || !$this->isMounted($strFolder))
  		{
  			throw new AccessDeniedException('Folder "' . $strFolder . '" is not mounted or is not a directory.');
  		}
  
  		/** @var Session $objSession */
  		$objSession = System::getContainer()->get('session');
  
  		// Empty clipboard
  		$arrClipboard = $objSession->get('CLIPBOARD');
  		$arrClipboard[$this->strTable] = array();
  		$objSession->set('CLIPBOARD', $arrClipboard);
  
  		$this->Files->mkdir($strFolder . '/__new__');
  		$this->redirect(html_entity_decode($this->switchToEdit($strFolder . '/__new__')));
  	}
docs: Create a new folder
  
  @throws AccessDeniedException
  @throws InternalServerErrorException