Are Python docstrings and comments stored in memory when a module is loaded?

Are Python docstrings and comments stored in memory when a module is loaded?

I've wondered if this is true, because I usually document my code well; may this affect memory usage?

Usually every Python object has a __doc__ method. Are those docstrings read from the file, or processed otherwise?

I've done searches here in the forums, Google and Mailing-Lists, but I haven't found any relevant information.

Do you know better?