With cursor placed just after the definition of can-instrument,
type C-u C-M-x, cider-eval-defun-at-point.
The function definition is evaled and instrumented.
With cursor placed just after the definition of can-not-instrument,
type C-u C-M-x, cider-eval-defun-at-point.
An error is thrown:
class clojure.lang.Symbol cannot be cast to class clojure.lang.Keyword (clojure.lang.Symbol and clojure.lang.Keyword are in unnamed module of loader 'app')