Is there any way to preserve the actual function, even after wrapping up with a decorator in python?

Question

    @dec_sub
    def sub(a, b):
        c= a-b
        return c
    
    def dec_sub(func):
        def wrapper(a, b):
            if a<b:
                a, b = b, a
            return func(a, b)
        return wrapper
    
    print(sub(48, 9)) # first digit is bigger than the second one yields positive return
    print(sub(1, 8)) # second digit is bigger than the first one also yields positive return

#Output : 39
          7

In the above code, how to use the function 'sub' in a usual way without the influence of the decorator?

Answer 1

You don't need to use decorator syntax to create a decorated function.

def sub(a, b):
    c = a - b
    return c


wrapped_sub = dec_sub(sub)

Or, you can use func_tools.wraps to create an object that exposes a reference to the original function.

from functools import wraps


def dec_sub(func):
    @wraps(func)
    def wrapper(a, b):
        if a<b:
            a, b = b, a
        return func(a, b)
    return wrapper

@dec_sub
def sub(a, b):
    c = a - b
    return c


sub(48, 9)   # the decorated function
sub.__wrapped__(48, 9)  # the original function