Is your intention to modify the original exception or make a copy? I ask because the code in [`within_construct`](https://github.com/bhb/test_construct/pull/1/files#diff-6b71d42cc79318d159a2994fb08e8371R13) would leave me to believe that we're creating a new exception (that has an annotated message) and are raising that. If we're not doing that, can we get rid of the block?