Python Decorators and Closures 3

Question 1

What does @staticmethod mean when applied to a method inside a class?

Accepted Answer

The method receives no implicit first argument — no self or cls

Answer

@staticmethod indicates the method does not receive an implicit first argument, making it essentially a regular function that belongs to the class's namespace.

Question 2

What is the key difference between @classmethod and @staticmethod?

Accepted Answer

@classmethod receives the class as its first argument (cls), @staticmethod receives no implicit argument

Answer

@classmethod receives the class itself as its first argument (conventionally called cls), while @staticmethod receives no implicit first argument at all.

Question 3

What is the output of the following code?

def make_multiplier(n):
    def multiplier(x):
        return x * n
    return multiplier

double = make_multiplier(2)
triple = make_multiplier(3)
print(double(5), triple(5))

Accepted Answer

10 15

Answer

double closes over n=2 and triple closes over n=3; each closure independently remembers its own captured value of n, so double(5) returns 10 and triple(5) returns 15.

Question 4

What is a common use of decorators in Python web frameworks like Flask?

Accepted Answer

Route registration — mapping URLs to handler functions with @app.route

Answer

In Flask, decorators like @app.route('/path') register URL routes to handler functions, which is one of the most widespread real-world applications of decorators.

Question 5

What happens to a decorated function if you do not use functools.wraps inside the wrapper?

Accepted Answer

The wrapped function loses its original metadata such as __name__ and __doc__

Answer

Without functools.wraps, the wrapper function's metadata (like __name__ and __doc__) replaces the original function's metadata, which causes problems with debugging and introspection tools.

Python Practice Test

Python Practice Test

Python Decorators and Closures 3