![flutter - Null Related Error - The argument type 'String? Function(String)' can't be assigned to the parameter type 'String? Function(String?)?' - Stack Overflow flutter - Null Related Error - The argument type 'String? Function(String)' can't be assigned to the parameter type 'String? Function(String?)?' - Stack Overflow](https://i.stack.imgur.com/JMYgl.png)
flutter - Null Related Error - The argument type 'String? Function(String)' can't be assigned to the parameter type 'String? Function(String?)?' - Stack Overflow
![30pcs Fishing Dart String for 1745 Rubber Tube Outdoor Hunting Catapult Shooting Accessories|Bow & Arrow| - AliExpress 30pcs Fishing Dart String for 1745 Rubber Tube Outdoor Hunting Catapult Shooting Accessories|Bow & Arrow| - AliExpress](https://ae01.alicdn.com/kf/H86d954e87818467c9eb6d608f7696759H/30pcs-Fishing-Dart-String-for-1745-Rubber-Tube-Outdoor-Hunting-Catapult-Shooting-Accessories.jpg_Q90.jpg_.webp)
30pcs Fishing Dart String for 1745 Rubber Tube Outdoor Hunting Catapult Shooting Accessories|Bow & Arrow| - AliExpress
![flutter - Null Related Error - The argument type 'String? Function(String)' can't be assigned to the parameter type 'String? Function(String?)?' - Stack Overflow flutter - Null Related Error - The argument type 'String? Function(String)' can't be assigned to the parameter type 'String? Function(String?)?' - Stack Overflow](https://i.stack.imgur.com/Gco6Q.png)