# Ensure variable is defined
try:
x
except NameError:
x = None
# Test whether variable is defined to be None
if x is None:
some_fallback_operation()
else:
some_operation(x)
# Ensure variable is defined
try:
x
except NameError:
x = None
# Test whether variable is defined to be None
if x is None:
some_fallback_operation()
else:
some_operation(x)