flutter The argument type ‘String?‘ can‘t be assigned to the parameter type ‘String‘.

The argument type 'String?' can't be assigned to the parameter type 'String'.

Change the return type of statusCode to String and provide a default value.

String get statusCode => statusCodes[this] ?? '';

When accessing a map, there is a chance that you will get a null return value if the key does not exist in the map. Simply providing a default value will allow this code to compile. That default value should never be used unless you add something to the enum without adding a value to the map as well.

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