...but maybe it is just me.
print(os.getcwd())
with lcd("/usr/bin"):
print(os.getcwd())
...prints the same location name twice, and it is clear that the cd didn't happen.
print(os.getcwd())
with lcd("/does/not/exist"):
print(os.getcwd())
...prints the same location name twice. lcd doesn't throw an error, which I would have thought it would.