Throw a BundeswahlValidationError with the message
Invalid <name>: <reason> when problem(value) finds a reason; otherwise return
value unchanged. Call it before any request, so a rejected input sends nothing.
Async methods call it inside their body, so the rejection arrives as a rejected
promise rather than a synchronous throw.
Throw a BundeswahlValidationError with the message
Invalid <name>: <reason>whenproblem(value)finds a reason; otherwise returnvalueunchanged. Call it before any request, so a rejected input sends nothing. Async methods call it inside their body, so the rejection arrives as a rejected promise rather than a synchronous throw.