Context Manager without Yield

Question

Can I have a context manager which occasionally does not yield, and in which case the code within the with statement are simply not executed?

import contextlib

@contextlib.contextmanager
def MayNotYield(to_yield):
  if to_yield:
    yield

with MayNotYield(True):  
  print 'This works.'

with MayNotYield(False):  
  print 'This errors.'

I could ask the user to wrap the with statement with a try-catch, but that is not preferred. I could also do the following but it is ugly too.

import contextlib

@contextlib.contextmanager
def AlwaysYields(to_yield):
  if to_yield:
    yield 1
  else:
    yield 2

with AlwaysYields(True) as result:
  if result == 1:
    print 'This works.'

Answer 1

Another option would be to just use a regular generator rather than a contextmanager; a plain generator won't have this restriction. But you'll have to use it with a "for" construct rather than using "with":

def MayNotYield(to_yield):
   if to_yield:
      yield

for _ in MayNotYield(True):
   print('This prints.')

for _ in MayNotYield(False):
   print('This does not.')