Is being pure function a requirement for Medley or could macro be consider for inclusion ? I ask this because I have a variation of `assoc-some` called `assoc-when` that works like that: ```clj (assoc-when m cond1 :k1 v1 cond2 :k2 v2 ...) ``` I first based it on Medley `assoc-some` but had to convert it into a macro so that values are not evaluated when associated condition is false.