decorator_example

my_list = []


def decorator(func):
    def wrapper(some_item):
        if isinstance(some_item, str):
            result = func(some_item)
            print(f"{some_item} added to the list")
            return result
        else:
            print(f"Error: {some_item} is not a string and won't be added to the list.")
            return None
    return wrapper


@decorator
def add_to_list(item):
    my_list.append(item)


add_to_list("hello")
add_to_list(123)  # not added
add_to_list("world")

print(my_list)  #  ['hello', 'world']