public function getMarkers($marker = NULL)
	{
		if($marker !== NULL && $this->markers !== NULL)
		{
			$result = [];
			
			foreach($this->markers as $check)
			{
				if($check instanceof $marker)
				{
					$result[] = $check;
				}
			}
			
			return $result;
		}
		
		return (array)$this->markers;
	}