Fixed a typo in docstring I happened upon.
diff --git a/Lib/SocketServer.py b/Lib/SocketServer.py
index 345a6d1..1e846fe 100644
--- a/Lib/SocketServer.py
+++ b/Lib/SocketServer.py
@@ -50,7 +50,7 @@
unix server classes.
Forking and threading versions of each type of server can be created
-using the ForkingServer and ThreadingServer mix-in classes. For
+using the ForkingMixIn and ThreadingMixIn mix-in classes. For
instance, a threading UDP server class is created as follows:
class ThreadingUDPServer(ThreadingMixIn, UDPServer): pass