toStringBody function
Implementation
String toStringBody(String className, Iterable<String> fields) {
final String fieldsToString = fields.fold('', (r, field) => r + '$field=\${this.$field},');
final String fieldsToStringCut = fieldsToString.length > 0?
fieldsToString.substring(0, fieldsToString.length - 1)
: fieldsToString;
return "return '$className(${fieldsToStringCut})';";
}