Clarify the os.fspath() documentation.
diff --git a/Doc/library/os.rst b/Doc/library/os.rst
index deabaeb..3dca86e 100644
--- a/Doc/library/os.rst
+++ b/Doc/library/os.rst
@@ -188,11 +188,12 @@
.. function:: fspath(path)
- Return the string representation of the path.
+ Return the file system representation of the path.
If :class:`str` or :class:`bytes` is passed in, it is returned unchanged;
- otherwise, the result of calling ``type(path).__fspath__`` is returned, or an
- exception is raised.
+ otherwise, the result of calling ``type(path).__fspath__`` is returned
+ (which is represented by :class:`os.PathLike`). All other types raise a
+ :exc:`TypeError`.
.. function:: getenv(key, default=None)