ios – NSInvalidArgumentException – Try to insert nil object from objects

I had the error under:

'*** -[__NSPlaceholderArray initWithObjects:count:]: try to insert nil object from objects[1]'

it occurs when I attempt to save texts from textfields utilizing saveInBackground or different form of saving methodology of Parse. As a result of code is little, all code is pasted under:

@IBAction func onSave(_ sender: Any) {
    let profile = PFObject(className: "Data")

    profile["preferredName"] = nameTextField.textual content!
    profile["major"] = majorTextField.textual content!
    profile["introduction"] = bioTextView.textual content!

    let segmentIndex = yearSegmented.selectedSegmentIndex
    UserDefaults.normal.set(segmentIndex, forKey: "segmentIndex")
    profile["year"] = yearSegmented.titleForSegment(at: segmentIndex)!

    print(profile.allKeys) // print keys in profile
    print(profile.worth(forKey: "introduction")!, profile.worth(forKey: "main")!,
    profile.worth(forKey: "yr")!, profile.worth(forKey: "preferredName")!) // print values in profile
    
    profile.saveInBackground(block: { (success, error) in // line the place the error occurs
        if success {
            UserDefaults.normal.set(true, forKey: "hasProfile")
            print("profile saved")
        } else {
            print("failed to save lots of profile")
        }
    })

I examined if any content material in profile is nil, however all keys and values are there and will be printed. I do not see something nil right here, so I can not perceive this error. If anybody might shed some mild to enlighten me, I might be be very grateful for this.

In case anybody wants the stack hint:

0   CoreFoundation                      0x00000001803f25e4 __exceptionPreprocess + 236
1   libobjc.A.dylib                     0x000000018019813c objc_exception_throw + 56
2   CoreFoundation                      0x00000001804775b4 -[__NSCFString characterAtIndex:].chilly.1 + 0
3   CoreFoundation                      0x0000000180474fc4 -[__NSPlaceholderArray initWithCapacity:].chilly.1 + 0
4   CoreFoundation                      0x00000001802ef138 -[__NSPlaceholderArray initWithObjects:count:] + 184
5   CoreFoundation                      0x00000001803dddec +[NSArray arrayWithObjects:count:] + 44
6   Parse                               0x0000000104eda478 -[PFTaskQueue enqueue:] + 380
7   Parse                               0x0000000104e78b2c -[PFObject saveInBackground] + 148
8   Parse                               0x0000000104e78c1c -[PFObject saveInBackgroundWithBlock:] + 68
9   StudyMate                           0x00000001041c59bc $s9StudyMate18EditViewControllerC6onSaveyyypF + 7276
10  StudyMate                           0x00000001041c5fe4 $s9StudyMate18EditViewControllerC6onSaveyyypFTo + 68
11  UIKitCore                           0x0000000184d81fa0 -[UIApplication sendAction:to:from:forEvent:] + 96
12  UIKitCore                           0x00000001842a7714 -[UIBarButtonItem _triggerActionForEvent:] + 176
13  UIKitCore                           0x000000018427fe24 __45-[_UIButtonBarTargetAction _invoke:forEvent:]_block_invoke + 36
14  UIKitCore                           0x000000018427fcd8 -[_UIButtonBarTargetAction _invoke:forEvent:] + 168
15  UIKitCore                           0x0000000184d81fa0 -[UIApplication sendAction:to:from:forEvent:] + 96
16  UIKitCore                           0x0000000184680bd8 -[UIControl sendAction:to:forEvent:] + 124
17  UIKitCore                           0x0000000184680fc0 -[UIControl _sendActionsForEvents:withEvent:] + 352
18  UIKitCore                           0x0000000184681010 -[UIControl _sendActionsForEvents:withEvent:] + 432
19  UIKitCore                           0x000000018467f8e8 -[UIControl touchesEnded:withEvent:] + 516
20  UIKitCore                           0x0000000184dc0af0 -[UIWindow _sendTouchesForEvent:] + 1104
21  UIKitCore                           0x0000000184dc25d4 -[UIWindow sendEvent:] + 4332
22  UIKitCore                           0x0000000184d9a390 -[UIApplication sendEvent:] + 784
23  UIKitCore                           0x0000000184e286f4 __dispatchPreprocessedEventFromEventQueue + 7520
24  UIKitCore                           0x0000000184e2a770 __processEventQueue + 6764
25  UIKitCore                           0x0000000184e22760 __eventFetcherSourceCallback + 184
26  CoreFoundation                      0x0000000180360820 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 24
27  CoreFoundation                      0x0000000180360720 __CFRunLoopDoSource0 + 204
28  CoreFoundation                      0x000000018035fab0 __CFRunLoopDoSources0 + 256
29  CoreFoundation                      0x000000018035a004 __CFRunLoopRun + 744
30  CoreFoundation                      0x0000000180359804 CFRunLoopRunSpecific + 572
31  GraphicsServices                    0x000000018c23660c GSEventRunModal + 160
32  UIKitCore                           0x0000000184d7bd2c -[UIApplication _run] + 992
33  UIKitCore                           0x0000000184d808c8 UIApplicationMain + 112
34  libswiftUIKit.dylib                 0x00000001b6766224 $s5UIKit17UIApplicationMainys5Int32VAD_SpySpys4Int8VGGSgSSSgAJtF + 100
35  StudyMate                           0x00000001041c7a9c $sSo21UIApplicationDelegateP5UIKitE4mainyyFZ + 104
36  StudyMate                           0x00000001041c7a24 $s9StudyMate11AppDelegateC5$mainyyFZ + 44
37  StudyMate                           0x00000001041c7b20 foremost + 28
38  dyld                                0x0000000104501cd8 start_sim + 20
39  ???                                 0x0000000104451088 0x0 + 4366602376
40  ???                                 0xb23a000000000000 0x0 + 12842577287400390656