public function all($keys = []) : Collection
	{
		if (count($keys) == 0) {
			$keys = $this->preferences->keys();
		}

		if (is_string($keys)) {
			$keys = [$keys];
		}

		return Collection::make($keys)->flatMap(function ($item) {
			if (isset($this->preferences[$item])) {
				$result[$item] = explode(',', $this->preferences[$item]);
			}
			return $result ?? [];
		});
	}