if you want to solve this kata with re module,
remember that in regex
you should be really carefull with '^' and '-',
especiall when it comes to the case of Square brackets('[]'),
'^' CANNOT be at the HEAD of a regex, BUT it can be '^' or in other part of a regex,
as well as
'-' CANNOT be in the MIDDLE of a regex, BUT it can be at the HEAD,
which is the most vital part you should have known.

in clojure this seems to expect white space between in front of \n should be swallowed in some test cases, and preserved in others