diff --git a/Lib/platform.py b/Lib/platform.py
index 75bc5f3b979..1e4abe64a1c 100755
--- a/Lib/platform.py
+++ b/Lib/platform.py
@@ -1336,9 +1336,10 @@ def python_implementation():
     """ Returns a string identifying the Python implementation.
 
         Currently, the following implementations are identified:
-        'CPython' (C implementation of Python),
-        'IronPython' (.NET implementation of Python),
-        'Jython' (Java implementation of Python).
+          'CPython' (C implementation of Python),
+          'IronPython' (.NET implementation of Python),
+          'Jython' (Java implementation of Python),
+          'PyPy' (Python implementation of Python).
 
     """
     return _sys_version()[0]