refactor: remove superfluous exception object.
refactor: remove superfluous exception object.

jeffbcross/ts2dart,hansl/ts2dart,jteplitz602/ts2dart,hterkelsen/ts2dart,hterkelsen/ts2dart,vicb/ts2dart,jteplitz602/ts2dart,jeffbcross/ts2dart,hansl/ts2dart,dart-archive/ts2dart,dart-archive/ts2dart,jacob314/ts2dart,dart-archive/ts2dart,jacob314/ts2dart,vicb/ts2dart