 public extension NSManagedObjectContext {
   
   /// Main NSManagedObjectContext of the app.
-  /// You can use it safely with UIKit, works on the main thread of the app.
+  /// Primary usage is UIKit, works on the main thread of the app.
   /// It's a singleton - always returns the same instance.
   public static var mainContext: NSManagedObjectContext {
     return CoreDuck.quack.mainContext

  /// Save NSManagedObjectContext
  ///
  /// - Parameters:
  ///   - block: execute block of code before save
  ///   - completion: context to save
  static func saveWithBlock(_ block: @escaping (_ localContext: NSManagedObjectContext) -> Void, completion: @escaping (_ success: Bool) -> Void) {
    let backgroundContext = NSManagedObjectContext.backgroundContext
    

  
  /// Background NSManagedObjectContext.
  /// Returns new instance of NSManagedObjectContext each time you access this variable.
  /// Use it for persisting changes to CoreData.
  public static var backgroundContext: NSManagedObjectContext {
    return CoreDuck.quack.backgroundContext
  }
