Mike
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Mike
In analogy with [mutable.Map](http://www.scala-lang.org/api/current/index.html#scala.collection.mutable.Map@put%28key:A,value:B%29:Option[B]). Otherwise one has to search twice, with ``` scala val old = m.get(k) m.update(k, v) old ``` which, admittedly, is what `MapLike` does but isn't efficient....