move _NONE from timeout to hub

gevent/hub.py

@@ -272,3 +272,12 @@ class Waiter(object):
     # can also have a debugging version, that wraps the value in a tuple (self, value) in switch()
     # and unwraps it in wait() thus checking that switch() was indeed called
 
+
+class _NONE(object):
+    "A special thingy you must never pass to any of gevent API"
+    __slots__ = []
+    def __repr__(self):
+        return '<_NONE>'
+
+_NONE = _NONE()
+

gevent/timeout.py

@@ -14,7 +14,7 @@ to arbitrary code.
 """
 
 from gevent import core
-from gevent.hub import getcurrent
+from gevent.hub import getcurrent, _NONE
 
 __all__ = ['Timeout',
            'with_timeout']
@@ -197,11 +197,3 @@ def with_timeout(seconds, function, *args, **kwds):
     finally:
         timeout.cancel()
 
-
-class _NONE(object):
-    __slots__ = []
-    def __repr__(self):
-        return '<_NONE>'
-
-_NONE = _NONE()
-