decorator function is not executing-CodePudding

I am trying to print the pattern as follows:

******
20
******

I used decorator function to print the pattern before and after main function. But my code is not printing the pattern only main function is getting executed. Please suggest how I can write the function in a better format.

Following is my code:

def banner(str1, len1):
    def decorator(func):
        def wrapper(*args1):
            new_line = '\n'
            str2 = str1 * len1
            return f'{str2}{new_line}{func(*args1)}{new_line}{str2}'
        return wrapper
    return decorator

@banner('*', 6)
def func1(a, b):
    print(a*b)

func1(5,4)

CodePudding user response：

You need to return a * b, not print it:

@banner('*', 6)
def func1(a, b):
    return a * b

Output:

>>> func1(5, 4)
'******\n20\n******'

>>> print(func1(5, 4))
******
20
******

The reason you need to return is because your wrapped function is called in the middle of that f-string, with func(*args1). With only a print statement in the function originally, your function defaulted to the implicit return None that all functions in Python default to if a return is not explicitly provided.