diff --git a/setup b/setup
index 6953df09d3c..25f5264d9dc 100644
--- a/setup
+++ b/setup
@@ -602,46 +602,6 @@ class FreeBSDHardware(Hardware):
                 if s:
                     self.facts['devices'][d.group(1)].append(s.group(1))
 
-def itersubclasses(cls, _seen=None):
-    """
-    itersubclasses(cls)
-
-    Generator over all subclasses of a given class, in depth first order.
-
-    >>> list(itersubclasses(int)) == [bool]
-    True
-    >>> class A(object): pass
-    >>> class B(A): pass
-    >>> class C(A): pass
-    >>> class D(B,C): pass
-    >>> class E(D): pass
-    >>> 
-    >>> for cls in itersubclasses(A):
-    ...     print(cls.__name__)
-    B
-    D
-    E
-    C
-    >>> # get ALL (new-style) classes currently defined
-    >>> [cls.__name__ for cls in itersubclasses(object)] #doctest: +ELLIPSIS
-    ['type', ...'tuple', ...]
-    """
-    
-    if not isinstance(cls, type):
-        raise TypeError('itersubclasses must be called with '
-                        'new-style classes, not %.100r' % cls)
-    if _seen is None: _seen = set()
-    try:
-        subs = cls.__subclasses__()
-    except TypeError: # fails only when cls is type
-        subs = cls.__subclasses__(cls)
-    for sub in subs:
-        if sub not in _seen:
-            _seen.add(sub)
-            yield sub
-            for sub in itersubclasses(sub, _seen):
-                yield sub
-
 class Network(Facts):
     """
     This is a generic Network subclass of Facts.  This should be further
@@ -663,7 +623,7 @@ class Network(Facts):
 
     def __new__(cls, *arguments, **keyword):
         subclass = cls
-        for sc in itersubclasses(Network):
+        for sc in Network.__subclasses__():
             if sc.platform == platform.system():
                 subclass = sc
         return super(cls, subclass).__new__(subclass, *arguments, **keyword)
@@ -969,14 +929,14 @@ class GenericBsdIfconfigNetwork(Network):
             for item in ifinfo[ip_type][0].keys():
                 defaults[item] = ifinfo[ip_type][0][item]
 
-class DarwinNetwork(GenericBsdIfconfigNetwork):
+class DarwinNetwork(GenericBsdIfconfigNetwork, Network):
     """
     This is the Mac OS X/Darwin Network Class.
     It uses the GenericBsdIfconfigNetwork unchanged
     """
     platform = 'Darwin'
 
-class FreeBSDNetwork(GenericBsdIfconfigNetwork):
+class FreeBSDNetwork(GenericBsdIfconfigNetwork, Network):
     """
     This is the FreeBSD Network Class.
     It uses the GenericBsdIfconfigNetwork unchanged