Decorators

from functools import partial, wraps

def print_result(func=None, *, prefix=''):
    if func is None:
        return partial(print_result, prefix=prefix)

    @wraps(func)
    def wrapper(*args, **kwargs):
        result = func(*args, **kwargs)
        print(f'{prefix}{result}')
        return result
    return wrapper

# ---------- #

@print_result
def add(a, b):
    return a + b

add(2, 3)  # outputs '5'

@print_result()
def add(a, b):
    return a + b

add(2, 3)  # outputs '5'

@print_result(prefix='The return value is ')
def add(a, b):
    return a + b

add(2, 3)  # outputs 'The return value is 5'