Experiment in making a “with” object that injects variables into the subjected scope and removes them at the end. One fatal flaw—see last comment. Inspired by: https://twitter.com/SwedishForSize/status/643146539897090048

with_scope.py

class scope(object):
	def __init__(self, **kargs):
		self.values = kargs
	def __enter__(self):
		import inspect
		frame, filename, lineno, module, code_context, idx = inspect.stack()[1]
		caller_args, caller_fargs, caller_kargs, caller_locals = inspect.getargvalues(frame)
		dest = caller_kargs if caller_kargs is not None else caller_locals
		self.saved = dict(dest)
		dest.update(self.values)
	def __exit__(self, exc_type, exc_value, traceback):
		import inspect
		frame, filename, lineno, module, code_context, idx = inspect.stack()[1]
		caller_args, caller_fargs, caller_kargs, caller_locals = inspect.getargvalues(frame)
		dest = caller_kargs if caller_kargs is not None else caller_locals
		for k in self.values:
			if k not in self.saved:
				del dest[k]
			else:
				dest[k] = self.saved[k]

def test_func():
	with scope(i="scoped i"):
		print i

def test():
	print j

with scope(i="scoped i", j="scoped j"):
	print i
	test()
try:
	print i #should fail
except NameError:
	print 'Cleanup succeeded'

#Fails because function scopes are not writable - the changes have no effect
test_func()