Flutter gsheets app fix part2

Job ID: 30748165

Budget: $10 – $30 USD

I have a gsheets post read app that works, and now I am trying to create a multiscreen app that uses that base app.
I have added all the code that I need, but I am getting an error, when trying to add more columns to the Map.
The function Future<void> addRow(Map<String, dynamic> row) async { is defined like this, and I need to change it so that it accepts more columns.
I am getting this error: type '_CompactLinkedHashSet<String>' is not a subtype of type 'Map<String, dynamic>' in type cast, and I also need to be able to get assistance in finishing my app.
Related categories: Android Dart Flutter