decorate class

>>> class Spam:
...     def __init__(self, value):
...             self.value = value
...     def yow(self):
...             print('Yow!')
...     def grok(self):
...             print('Grok!')
... 
>>> vars(Spam)
mappingproxy({'__module__': '__main__', '__init__': <function Spam.__init__ at 0x7f95b61a0d08>, 'yow': <function Spam.yow at 0x7f95b61a0d90>, 'grok': <function Spam.grok at 0x7f95b61b0048>, '__dict__': <attribute '__dict__' of 'Spam' objects>, '__weakref__': <attribute '__weakref__' of 'Spam' objects>, '__doc__': None})
>>> vars(Spam).items()
dict_items([('__module__', '__main__'), ('__init__', <function Spam.__init__ at 0x7f95b61a0d08>), ('yow', <function Spam.yow at 0x7f95b61a0d90>), ('grok', <function Spam.grok at 0x7f95b61b0048>), ('__dict__', <attribute '__dict__' of 'Spam' objects>), ('__weakref__', <attribute '__weakref__' of 'Spam' objects>), ('__doc__', None)])

>>> 
>>> def boo(func):
...     def wrapper(*args, **kwargs):
...             print('hello from inside')
...             return func(*args, **kwargs)
...     return wrapper
... 
>>>

>>> 
>>> def boo_methods(cls):
...     for key, value in vars(cls).items():
...             if callable(value):
...                     setattr(cls, key, boo(value))
...     return cls
... 
>>>

>>> 
>>> @boo_methods
... class Spam:
...     def __init__(self, value):
...             self.value = value
...     def yow(self):
...             print('Yow!')
...     def grok(self):
...             print('Grok!')
... 
>>> s = Spam(2)
hello from inside
>>> s.yow()
hello from inside
Yow!
>>> s.grok()
hello from inside
Grok!
>>>