diff --git a/Lib/posixpath.py b/Lib/posixpath.py
index 73624835020..492c415aa5d 100644
--- a/Lib/posixpath.py
+++ b/Lib/posixpath.py
@@ -188,6 +188,7 @@ def ismount(path):
         # It doesn't exist -- so not a mount point. :-)
         return False
     else:
+        # A symlink can never be a mount point
         if stat.S_ISLNK(s1.st_mode):
             return False