1INPUT_TYPE = "in"
 2OUTPUT_TYPE = "out"
 3SEPARATOR = ", "
 4
 5def type_check(io_type=INPUT_TYPE):
 6    """ Decorator for type checking on function arguments or return value."""
 7    def argument_check(*expected_types):
 8        def decorator(func):
 9            def body_of_decorator(*args, **kwargs):
10                expected_types_for_print = SEPARATOR.join(map(str, expected_types))
11                if io_type == INPUT_TYPE:
12                    for arg in args:
13                        if not isinstance(arg, expected_types):
14                            print(f"Invalid input arguments, expected {expected_types_for_print}!")
15                            break
16                result = func(*args, **kwargs)
17                if io_type == OUTPUT_TYPE and not isinstance(result, expected_types):
18                    print(f"Invalid output value, expected {expected_types_for_print}!")
19                return result
20            return body_of_decorator
21        return decorator
22    return argument_check