addToTheEndOfClass function
Implementation
addToTheEndOfClass( String filePath,String content)async {
final file = File(filePath);
final String fileString = await file.readAsString();
fileString.trim();
int lastIndex = fileString.lastIndexOf('}');
String newFileContent = "${fileString.substring(0,lastIndex)} \n ${content.trim()} \n }";
file.writeAsString(newFileContent,mode: FileMode.write);
}