public function getFlatListOfExtensions()
	{
		if (!isset($this->flatExtentions))
		{
			$this->flatExtentions = [];

			foreach ($this->getFlatListOfFiles() as $file)
			{
				$this->flatExtentions[] = $file->getExtension();
			}

			$this->flatExtentions = array_count_values($this->flatExtentions);
		}

		return $this->flatExtentions;
	}