This smells as being a need that comes as a consequence of using a dynamically-typed language. Because the example given seems to be just getting rid of the usage of a certain method, to replace with a new one. In a statically typed language, e.g. C#, you just mark the old method with an [Obsolete] attribute and go fix all the warnings. (Granted, a tool that replaces all these usages is also useful, but to me, there are much more complex ways of technical debt than just obsolete methods.)