Raise a Python UserWarning if the `value` is not None. This is to be used with a TypedField preset or postset hook.
(instance, value)
| 23 | |
| 24 | |
| 25 | def field(instance, value): |
| 26 | """Raise a Python UserWarning if the `value` is not None. This is to be |
| 27 | used with a TypedField preset or postset hook. |
| 28 | """ |
| 29 | warn(value) |
| 30 | |
| 31 | |
| 32 | def warn(value): |