A more concise example might be as follows:
#/usr/bin/env python3 from functools import wraps def wrapper(method): @wraps(method) def _impl(self, *method_args, **method_kwargs): method_output = method(self, *method_args, **method_kwargs) return method_output + "!" return _impl class Foo: @wrapper def bar(self, word): return word f = Foo() result = f.bar("kitty") print(result) Which will print:
kitty!