It is confusing, but it's also kind of the standard pattern for decorators in Python, so it's a useful example. The decorator syntax itself is just simple synt

It is confusing, but it's also kind of the standard pattern for decorators in Python, so it's a useful example. The decorator syntax itself is just simple syntax sugar for replacing the decorated function (add) with the return value of the decorator function (show_call). The example is essentially equivalent to this: def show_call(func): ... def add(x, y): return x + y add = show_call(add) So show_call has to return the function we want as a replacement, which is the nested "out" function here. The "@wraps" thing is not strictly necessary but updates the new function object to have the same name as the original.