issue27186: add PathLike ABC
diff --git a/Lib/os.py b/Lib/os.py
index 0131ed8..e7d089e 100644
--- a/Lib/os.py
+++ b/Lib/os.py
@@ -22,7 +22,7 @@
 """
 
 #'
-
+import abc
 import sys, errno
 import stat as st
 
@@ -1125,3 +1125,18 @@
 
             raise TypeError("expected str, bytes or os.PathLike object, not "
                             + path_type.__name__)
+
+class PathLike(abc.ABC):
+    """
+    Abstract base class for implementing the file system path protocol.
+    """
+    @abc.abstractmethod
+    def __fspath__(self):
+        """
+        Return the file system path representation of the object.
+        """
+        raise NotImplementedError
+
+    @classmethod
+    def __subclasshook__(cls, subclass):
+        return hasattr(subclass, '__fspath__')