Suppose I already had two function functions like: def strip_prefix(prefix, str): ... def name_from_fooid(fooid): return strip_prefix("foo",

Suppose I already had two function functions like: def strip_prefix(prefix, str): ... def name_from_fooid(fooid): return strip_prefix("foo", id) Now is it better to call `name_from_fooid` or to call `strip_prefix` directly? It depends on the high-level semantics we are trying to express. But assuming we really are extracting a Name from a FooId, then the former is probably better. But then if you want a name_from_fooid function, it's just an implementation detail that you happen to implement it on top of a strip_prefix utility.