code: public function getAllowedCalendars()
  	{
  		if ($this->User->isAdmin)
  		{
  			$objCalendar = Contao\CalendarModel::findAll();
  		}
  		else
  		{
  			$objCalendar = Contao\CalendarModel::findMultipleByIds($this->User->calendars);
  		}
  
  		$return = array();
  
  		if ($objCalendar !== null)
  		{
  			while ($objCalendar->next())
  			{
  				$return[$objCalendar->id] = $objCalendar->title;
  			}
  		}
  
  		return $return;
  	}
docs: Return the IDs of the allowed calendars as array
  
  @return array