contextlib_contextmanager.py

#!/usr/bin/env python


import contextlib


@contextlib.contextmanager
def make_context():
    print '  entering'
    try:
        yield {}
    except RuntimeError, err:
        print ' ERROR:', err
    finally:
        print ' exiting'

print 'Normal:'
with make_context() as value:
    print '  inside with statement:', value

print '\nHandled error:'
with make_context() as value:
    raise RuntimeError('showing example of handling an error')

print '\nUnhandled error:'
with make_context() as value:
    raise ValueError('this exception is not handled')