Most programming happens in nominally typed languages where the above isn't trivially possible. To be fair that example is contrived, but you can imagine operations happening on large dicts where only a small subset of the fields are necessary.
Most programming happens in nominally typed languages where the above isn't trivially possible. To be fair that example is contrived, but you can imagine operations happening on large dicts where only a small subset of the fields are necessary.
This is actually a relatively common example of the benefits of either polymorphism (for the a.add(b) version) or generic methods/templates. You'll actually find libraries that have a method or template function like this in C++, Java, C#, and other commonly used static languages.