Cannot create an inferred NSMappingModel with a nil source model

I'm trying to see if the mapping of my two models is inferred using lightweight migration. This is because I'm not able to retrieve entities created using old model. I get empty array upon fetching.

The code I've written is as follows...

NSError *error;

NSManagedObjectModel *expensesModel1 = [[NSManagedObjectModel alloc] initWithContentsOfURL:expensesModel1URL];

 NSManagedObjectModel *expensesModel2 = [[NSManagedObjectModel alloc] initWithContentsOfURL:expensesModel2URL];

NSMappingModel *mappingModel = [NSMappingModel inferredMappingModelForSourceModel:expensesModel1 destinationModel:expensesModel2 error:&error];

Now, both URLs are set, i.e., they are not Nil. But, both the NSManagedObjectModel objects (expensesModel1, expensesModel2 )remain nil.

The error I get is...

2021-12-28 14:39:21.226111+0530 Expenses Pro[2248:634959] [error] error:  Failed to load model as no file exists at path '/Users/neeravkothari/Current Project/Expenses Pro v2/Expenses Pro/Expenses Pro/Model/Core Data/Expenses.xcdatamodeld/Expenses.xcdatamodel'

CoreData: error:  Failed to load model as no file exists at path '/Users/neeravkothari/Current Project/Expenses Pro v2/Expenses Pro/Expenses Pro/Model/Core Data/Expenses.xcdatamodeld/Expenses.xcdatamodel'

2021-12-28 14:39:21.226201+0530 Expenses Pro[2248:634959] [error] error: Unable model at path (file is zero bytes) '/Users/neeravkothari/Current Project/Expenses Pro v2/Expenses Pro/Expenses Pro/Model/Core Data/Expenses.xcdatamodeld/Expenses.xcdatamodel'

CoreData: error: Unable model at path (file is zero bytes) '/Users/neeravkothari/Current Project/Expenses Pro v2/Expenses Pro/Expenses Pro/Model/Core Data/Expenses.xcdatamodeld/Expenses.xcdatamodel'

I get a similar 4 line error for the destination model Expenses 2.xcdatamodel What is the issue here?

Neerav