opParamDeclaration function
Implementation
String opParamDeclaration(DocumentNode doc, List<InputValueDefinitionNode> args) {
String str = '';
args.forEach((arg) {
str += ' ${arg.type.isNonNull ? 'required ' : ''} ${arg.type.toDartType()} ${arg.name.value},';
});
return str.isNotEmpty ? '{ ${str} }' : '';
}