Return ``True`` if pathname *path* is a :dfn:`mount point`: a point in a

file system where a different file system has been mounted. On POSIX, the

function checks whether *path*'s parent, :file:`path/..`, is on a different

device than *path*, or whether :file:`path/..` and *path* point to the same

function checks whether *path*'s parent, :file:`{path}/..`, is on a different

device than *path*, or whether :file:`{path}/..` and *path* point to the same

i-node on the same device --- this should detect mount points for all Unix

and POSIX variants. On Windows, a drive letter root and a share UNC are

and POSIX variants. It is not able to reliably detect bind mounts on the

same filesystem. On Windows, a drive letter root and a share UNC are

always mount points, and for any other path ``GetVolumePathName`` is called

to see if it is different from the input path.