nulltype_custom_sentinel_value_falsy_singleton_quickstart.py

1from nulltype import Null
2
3# Null is a singleton, and it's always False in a boolean context
4if not Null:
5    print("Null is falsy, as expected.")
6
7# You can use it as a default value in functions
8def my_function(value=Null):
9    if value is Null:
10        print("No value was provided.")
11    else:
12        print(f"Value provided: {value}")
13
14my_function()
15my_function(10)
16
17# You can also create your own custom null types
18from nulltype import NullType
19
20class MySentinel(NullType):
21    pass
22
23sentinel = MySentinel()
24if not sentinel:
25    print("Custom sentinel is also falsy.")