Index: Lib/multiprocessing/synchronize.py
===================================================================
--- Lib/multiprocessing/synchronize.py	(revision 72571)
+++ Lib/multiprocessing/synchronize.py	(working copy)
@@ -278,6 +278,9 @@
         finally:
             self._cond.release()
 
+    def __bool__(self):
+        return self.is_set()
+
     def set(self):
         self._cond.acquire()
         try:
Index: Lib/threading.py
===================================================================
--- Lib/threading.py	(revision 72571)
+++ Lib/threading.py	(working copy)
@@ -353,6 +353,9 @@
     def is_set(self):
         return self._flag
 
+    def __bool__(self):
+        return self.is_set()
+
     isSet = is_set
 
     def set(self):