Uncaught exception:
  1. #<&failed-type-check predicate: external?>
  2. #<&message message: "type check failed">
  3. #<&origin origin: external-null?>
  4. #<&irritants irritants: (#<procedure simple-format>)>
  5. #<&source file: "hoot/errors.scm" line: 95 column: 22>