contextlib

>>> import contextlib
>>> @contextlib.contextmanager
... def make_context():
...     print 'enter'
...     try:
...         yield {}
...     except RuntimeError, err:
...         print 'error', err
...     finally:
...         print 'exit'
... 
>>> with make_context() as c:
...     print c
... 
enter
{}
exit
>>>