runcall(): Expose the return value of the profiled function; this allows

changing an application to collect profile data on one part of the
    app while still making use of the profiled component, without relying
    on side effects.

Lib/hotshot/__init__.py

@@ -35,4 +35,4 @@ class Profile:
         return self
 
     def runcall(self, func, *args, **kw):
-        self._prof.runcall(func, args, kw)
+        return self._prof.runcall(func, args, kw)