rec

import dek

@dek
def print_before(pfunc, label='label'):
    print(label, pfunc)
    return pfunc()

rec

# Correct decorator for an optional parameter
def print_before4(label='label'):

    def decorator(func):

        @functools.wraps(func)
        def wrapped(*args, **kwargs):
            print(label, args, kwargs)
            return func(*args, **kwargs)

rec

@print_before3()
def mj1(a, b, c):
    pass


@print_before3('OK')
def mj2(one, two, three):
    pass

rec

@print_before3()
def important(lives, money, valuables=None):
    pass
  
  
@print_before3('BORING:')
def dull(*args, **kwds):
    pass

  

rec

# Almost right
def print_before3(label='DEBUG:'):
  
    def decorator(func):
      
        @functools.wraps(func)
        def wrapped(*args, **kwds):
            print(label, func.__name__, args, kwds)
            return func(*args, **kwds)
          

rec

# Version 3
def print_before2(label):
  
    def decorator(func):
      
        @functools.wraps(func)
        def wrapped(*args, **kwds):
            print(label, func.__name__, args, kwds)
            return func(*args, **kwds)
          

rec

# WRONG
def print_before(func, label):
  
    @functools.wraps(func)
    def wrapped(*args, **kwds):
        print(label, func.__name__, args, kwds)
        return func(*args, **kwds)
      
    return wrapped
  

rec

import functools


def print_before(func):
  
    @functools.wraps(func)
    def wrapped(*args, **kwds):
        print(func.__name__, args, kwds)
        return func(*args, **kwds)
      

rec

@print_before
def important(lives, money, valuables=None):
    """Do big, important things!!"""
    pass


>>> important(23, 105.17, valuables=['dogs'])

important (23, 105.17) {'valuables': ['dogs']}

rec

def print_before(func):
    
    def wrapped(*args, **kwds):
        print('Before:', func.__name__, args, kwds)
        return func(*args, **kwds)
    
    return wrapped