gistfile1.py

>>> def foo():
...   raise StopIteration
... 
>>> list(foo())
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<stdin>", line 2, in foo
StopIteration
>>> def foo():
...   raise StopIteration
...   yield
... 
>>> list(foo())
[]