mapOrNull<TResult extends Object?>  method 
- @optionalTypeArgs
- TResult? $default(- _RepoOp value
 
A variant of map that fallback to returning null.
It is equivalent to doing:
switch (sealedClass) {
  case final Subclass value:
    return ...;
  case _:
    return null;
}
Implementation
@optionalTypeArgs TResult? mapOrNull<TResult extends Object?>(TResult? Function( _RepoOp value)?  $default,){
final _that = this;
switch (_that) {
case _RepoOp() when $default != null:
return $default(_that);case _:
  return null;
}
}