2018-09-19 15:37:33.253482+0100 <redacted>-beta[3715:1010421] -[Swift._EmptyArrayStorage _getValue:forType:]: unrecognized selector sent to instance 0x107e6c290
2018-09-19 15:37:33.254312+0100 <redacted>-beta[3715:1010421] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[Swift._EmptyArrayStorage _getValue:forType:]: unrecognized selector sent to instance 0x107e6c290'

mutableAttributedString.addAttribute(NSAttributedString.Key.underlineStyle, value: NSUnderlineStyle.none.rawValue, range: range)
                                                                                   ^~~~~ 'none' is unavailable: use [] to construct an empty option set