title: NSEntityDescription.insertNewObject Function Causing Crash in Swift 3
body: <p>I'm following this introduction tutorial to <a href="https://www.youtube.com/watch?v=3IDfgATVqHw/" rel="nofollow noreferrer">this tutorial</a>, and am completely new to Core Data.  </p>
  
  <p>Here is the class that produces the error (however the error sends me to the first line of AppDelegate with a sigabrt.  The line that begins "let newUser" seems to produce the error, because the error dissappears when I comment it out.</p>
  
  <pre><code>@IBAction func btnSave(){
      let appDel:AppDelegate = (UIApplication.shared().delegate as! AppDelegate)
      let context:NSManagedObjectContext = appDel.persistentContainer.viewContext
      let newUser = NSEntityDescription.insertNewObject(forEntityName: "Users", into: context) as NSManagedObject
  
      do {
          try context.save()
      } catch {}
  
      print("Object Saved.")    
  }
  </code></pre>
  
  <p><a href="https://stackoverflow.com/questions/38427366/ios-10-coredata-insert-new-object-sig-abrt">This problem looks similar, but the answer is confusing to me and seems a bit overcomplicated</a></p>
  
  <p>Since no one has posted about this error on the above Youtube video's comment section yet, I assume this is an error due to a change in Swift 3 (there was another error due to a change in Swift 2 which is documented in the comments).</p>
  
  <p>Any help is greatly appreciated!</p>
  
  <pre><code>frame #0: 0x00000001067cbf06 libsystem_kernel.dylib`__pthread_kill + 10
  frame #1: 0x00000001068ec4ec libsystem_pthread.dylib`pthread_kill + 90
  frame #2: 0x000000010651e0b3 libsystem_c.dylib`abort + 129
  frame #3: 0x00000001067ea43a libc++abi.dylib`abort_message + 266
  frame #4: 0x000000010680ea9f libc++abi.dylib`default_terminate_handler() + 267
  frame #5: 0x00000001055be59f libobjc.A.dylib`_objc_terminate() + 103
  frame #6: 0x000000010680bc09 libc++abi.dylib`std::__terminate(void (*)()) + 8
  frame #7: 0x000000010680b894 libc++abi.dylib`__cxa_rethrow + 99
  frame #8: 0x00000001055be4b7 libobjc.A.dylib`objc_exception_rethrow + 40
  frame #9: 0x00000001030f7bf1 CoreFoundation`CFRunLoopRunSpecific + 433
  frame #10: 0x000000010850ea48 GraphicsServices`GSEventRunModal + 161
  frame #11: 0x0000000103b30e8b UIKit`UIApplicationMain + 159
  * frame #12: 0x0000000102b5dc6f CoreDataYoutube`main + 111 at AppDelegate.swift:5
  frame #13: 0x00000001064726bd libdyld.dylib`start + 1
  </code></pre>