code: public final ImmutableList<TypeToken<? extends Throwable>> getExceptionTypes() {
      ImmutableList.Builder<TypeToken<? extends Throwable>> builder = ImmutableList.builder();
      for (Type type : getGenericExceptionTypes()) {
        // getGenericExceptionTypes() will never return a type that's not exception
        @SuppressWarnings("unchecked")
        TypeToken<? extends Throwable> exceptionType =
            (TypeToken<? extends Throwable>) TypeToken.of(type);
        builder.add(exceptionType);
      }
      return builder.build();
    }
docs: Returns all declared exception types of this {@code Invokable}.