def decorator(func):
    def wrapper:
        print(f"Before the function.")
        func()
        print(f"After the function.")
    return wrapper

# Tells the function, it is a decorator.
@decorator
def hello():
    print("Hello, World!")

# Call the function
hello()

The provided Python code defines a decorator named decorator that takes a function func as its argument. The decorator encapsulates the original function's behavior within a wrapper function. This wrapper function, when invoked, prints a message before and after calling the original function. The intention is to augment the functionality of any decorated function. Following the decorator definition, the code applies the @decorator syntax to the hello function, signaling that it should be decorated by the decorator function. When the hello function is subsequently called, it not only prints "Hello, World!" but also executes the additional behavior defined in the wrapper, showcasing the extended capabilities introduced by the decorator.