In the above code, we have defined a static function called `getNameById` inside the `User` class. The function takes an `$id` parameter, which is used to query the database and retrieve the name of the user with the given ID. In this example, we are just returning a dummy name for demonstration purposes. To use this function, we must first get the user ID and then pass it to the `getNameById` function. The returned name is then stored in the `$user_name` variable and printed to the screen. It is difficult to determine the package library that contains this function without additional context. However, it is likely that it is part of a larger library or framework that deals with user authentication or management.