fun <T : Any> ArgumentMapperBuilder<T?>.toNullOr(): ArgumentToNullOrMapperBuilder<T> (source)
Maps each argument to null if it is already null and if not, then ...
... what happens otherwise needs to be specified in the next step.
Notice, a future version might constrain T with a lower bound Nothing?.
Returns
The mapped ArgumentMapperBuilder.first and ArgumentMapperBuilder.others.