public static function make_human_readable_filesize($bytes) {
		$units = array('B', 'KB', 'MB', 'GB', 'TB', 'PB');
		$num_units = count($units);
		$size = $bytes;
		foreach ($units as $i => $unit) {
			if ($size < 1024 || (($i + 1) === $num_units)) {
				return round($size, 2).$unit;
			}
			$size = $size / 1024;
		}
		return $size;
	}