This patch shows changes done to asyncio.tasks.Task._step() from CPython 3.4.2.

--- tasks.py	2015-01-01 10:51:40.707114866 +0200
+++ uasyncio.py	2015-01-01 10:54:20.172402890 +0200
@@ -46,13 +55,16 @@
                 # Bare yield relinquishes control for one event loop iteration.
                 self._loop.call_soon(self._step)
             elif inspect.isgenerator(result):
+                #print("Scheduling", result)
+                self._loop.create_task(result)
+                self._loop.call_soon(self._step)
                 # Yielding a generator is just wrong.
-                self._loop.call_soon(
-                    self._step, None,
-                    RuntimeError(
-                        'yield was used instead of yield from for '
-                        'generator in task {!r} with {}'.format(
-                            self, result)))
+#                self._loop.call_soon(
+#                    self._step, None,
+#                    RuntimeError(
+#                        'yield was used instead of yield from for '
+#                        'generator in task {!r} with {}'.format(
+#                            self, result)))
             else:
                 # Yielding something else is an error.
                 self._loop.call_soon(