ModelController+Delete.swift

extension ModelController {
	
	func delete(by objectID: NSManagedObjectID) {
		
		let managedObject = context.object(with: objectID)
		context.delete(managedObject)
	}
	
	func delete<M: NSManagedObject>(_ type: M.Type, predicate: NSPredicate?=nil) {
		
		if let objects = fetch(type, predicate: predicate) {
			for modelObject in objects {
				delete(by: modelObject.objectID)
			}
		}
		
		if context.deletedObjects.count > 0 {
			save()
		}
	}
}