Options for a singleton "Empty" value with pickability and repr

empty_values_options.py

from tested import validate_codec


Empty1 = type('Empty', (), {})()
print("\nEmpty1 = type('Empty', (), {})()")
print(f"{validate_codec(Empty1)=}")


_Empty2 = type('Empty', (), {})
_Empty2.__module__ = __name__
Empty2 = _Empty2()
print("\nsame, with _Empty2.__module__ = __name__; Empty2 = _Empty()")
print(f"{validate_codec(Empty2)=}")

_Empty3 = type('Empty', (), {})
Empty3 = _Empty3()
Empty3.__module__ = __name__
print("\nwith Empty3.__module__ = __name__ (added to instance instead of class)")
print(f"{validate_codec(Empty3)=}")


class _Empty4: ...
Empty4 = _Empty4()
print("\nDefining as ``class _Empty4: ...``")
print(f"{validate_codec(Empty4)=}")


class Empty5: ...

Empty5 = Empty5()  # overridding class (now no one else can use it!"

print("\nOverwriding class Empty5 with instance Empty5")
print(f"{validate_codec(Empty5)=}")


class _Empty6:
    def __repr__(self):
        return f"Empty"

Empty6 = _Empty6()

print("\nLike Empty4, but with nice repr)")
print(f"{validate_codec(Empty6)=}")