Issue #14482: Raise a ValueError, not a NameError, when trying to create
a multiprocessing Client or Listener with an AF_UNIX type address under
Windows.  Patch by Popa Claudiu.
diff --git a/Lib/multiprocessing/connection.py b/Lib/multiprocessing/connection.py
index fa6f7b3..8bb0a3b 100644
--- a/Lib/multiprocessing/connection.py
+++ b/Lib/multiprocessing/connection.py
@@ -101,6 +101,10 @@
     if sys.platform != 'win32' and family == 'AF_PIPE':
         raise ValueError('Family %s is not recognized.' % family)
 
+    if sys.platform == 'win32' and family == 'AF_UNIX':
+        # double check
+        if not hasattr(socket, family):
+            raise ValueError('Family %s is not recognized.' % family)
 
 def address_type(address):
     '''