public function getAllowedMimeTypesAsHumanString($lastSeparator = null) {
		$separator = ', ';

		$str = \implode($separator, $this->getAllowedMimeTypesAsArray());

		if ($lastSeparator !== null) {
			$lastSeparatorPosition = \strrpos($str, $separator);

			if ($lastSeparatorPosition !== false) {
				$str = \substr_replace($str, $lastSeparator, $lastSeparatorPosition, \strlen($separator));
			}
		}

		return $str;
	}