Change owner user and group of the given path.
user and group can be the uid/gid or the user/group names, and in that case,
they are converted to their respective uid/gid.
If dir_fd is set, it should be an open file descriptor to the directory to
be used as the root of *path* if it is relative.
If follow_symlinks is set to False and the last element of the path is a
symbolic link, chown will modify the link itself and not the file being
referenced by the link.