decorating a method in multiple child classes

[1x7y2z9]

Say, we have a (parent) class P.
It has N child classes C1(P), C2(P) ... CN(P)

Each of the child classes defines (differently) a method func().

I wish to decorate all of the CX.func() in the same way. One way to
do this is to add a decorator to each of the derived classes. But
this is tedious and involves modifying multiple files.

Is there a way to modify the parent class and have the same effect?
Or some other way neater than the above?

Thanks.

visual:
class P(object):
...

class C1(P):
def func(self, ...):
...

class C2(P):
def func(self, ...):
...

[Duncan Booth]

1x*****@gmail.c om wrote:

I wish to decorate all of the CX.func() in the same way. One way to
do this is to add a decorator to each of the derived classes. But
this is tedious and involves modifying multiple files.

Is there a way to modify the parent class and have the same effect?
Or some other way neater than the above?

Use a metaclass.

>>def decorate(f):

print "decorating ", f
return f

>>class meta(type):

def __init__(self, name, bases, dictionary):
if 'func' in dictionary:
dictionary['func'] = decorate(dictio nary['func'])
type.__init__(s elf, name, bases, dictionary)

>>class P(object):

__metaclass__ = meta

>>class C1(P):

def func(self): pass
decorating <function func at 0x0119B370>

>>>