## No value
Sentinel values to express missing keys or values, 
where None has it's own meaning, for example in jsom

**warn:** does not support static analysis (there is not way to make it right now)

### Examples:
```python
from no_value import NoValue 
def foo(val: int | NoValue) -> None:
    if val is NoValue:
        print("missing")
    else:
        print(val)


foo(NoValue)
foo(123)
```