What are some common errors when using decorators in Python?

What are some common errors when using decorators in Python?

Some common errors include forgetting to return the wrapper function, using the wrong number of arguments, and not handling exceptions properly.

Can you give me an example of a decorator that has a common error?

Sure! A common error is forgetting to return the wrapper function. Here's an example:

def my_decorator(func):
    def wrapper():
        print('Something is happening before the function is called.')
        func()  # Missing return statement here
    return wrapper

@my_decorator
def say_hello():
    print('Hello!')

say_hello()  # This will not work as expected.

What happens if I forget to return the wrapper?

If you forget to return the wrapper, the decorated function will not execute as intended. Instead, it will return None, and you'll lose the original function's behavior.

How can I fix that error?

To fix it, simply add a return statement in the wrapper function:

def my_decorator(func):
    def wrapper():
        print('Something is happening before the function is called.')
        return func()  # Now it returns the result of the original function
    return wrapper