Fix RST syntax error in README.
@@ -744,6 +744,7 @@ appropriately. The exception handler will take as arguments the exception
itself, the pubsub object, and the worker thread returned by `run_in_thread`.
.. code-block:: pycon
+
>>> p.subscribe(**{'my-channel': my_handler})
>>> def exception_handler(ex, pubsub, thread):
>>> print(ex)
