How to Check if a Value is Undefined in Python

In Python, you can check if a value is undefined using the 'is' operator to compare the value with the 'None' keyword, which represents the absence of a value. Here's an example:

x = None
if x is None:
    print('Value is undefined')
else:
    print('Value is defined')

This code will output 'Value is undefined' because the variable 'x' is assigned to None, which means it has no value. If you assign a value to 'x', the code will output 'Value is defined'.