Help hook Message app

I know the correct view is: CKBalloonTextView : UITextView
and this is the header:

@interface CKBalloonTextView : UITextView <NSLayoutManagerDelegate> {
    NSAttributedString *_attributedText;
    float _capOffsetFromBoundsTop;
    <CKBalloonTextViewInteractionDelegate> *_interactionDelegate;
    float _lastLineBaselineOffsetFromBoundsTop;
    BOOL _singleLine;
}

@property (nonatomic, copy) NSAttributedString *attributedText;
@property (nonatomic) float capOffsetFromBoundsTop;
@property (readonly, copy) NSString *debugDescription;
@property (readonly, copy) NSString *description;
@property (readonly) unsigned int hash;
@property (nonatomic) <CKBalloonTextViewInteractionDelegate> *interactionDelegate;
@property (nonatomic) float lastLineBaselineOffsetFromBoundsTop;
@property (getter=isSingleLine, nonatomic) BOOL singleLine;
@property (readonly) Class superclass;

- (void)_interactionStartedFromPreviewItemController:(id)arg1;
- (void)_interactionStoppedFromPreviewItemController:(id)arg1;
- (id)attributedText;
- (float)capOffsetFromBoundsTop;
- (void)dealloc;
- (id)description;
- (void)didMoveToWindow;
- (id)initReadonlyAndUnselectableWithFrame:(struct CGRect { struct CGPoint { float x_1_1_1; float x_1_1_2; } x1; struct CGSize { float x_2_1_1; float x_2_1_2; } x2; })arg1 textContainer:(id)arg2;
- (id)interactionDelegate;
- (BOOL)isSingleLine;
- (float)lastLineBaselineOffsetFromBoundsTop;
- (void)setAttributedText:(id)arg1;
- (void)setCapOffsetFromBoundsTop:(float)arg1;
- (void)setInteractionDelegate:(id)arg1;
- (void)setLastLineBaselineOffsetFromBoundsTop:(float)arg1;
- (void)setSingleLine:(BOOL)arg1;
- (struct CGSize { float x1; float x2; })sizeThatFits:(struct CGSize { float x1; float x2; })arg1 textAlignmentInsets:(struct UIEdgeInsets { float x1; float x2; float x3; float x4; }*)arg2 isSingleLine:(BOOL*)arg3;

@end

I have to grab the (id)arg1 of this function - (void)setAttributedText:(id)arg1;
but only for select sms ballon...