decortaors.py

class foo:
    def __init__(self):
        self.a = "abc"
        
    def defB(self):
        self.b = "B"
        
    def printB(self):
        print self.b
        
class bar:
    def __init__(self):
        self.a = "abc"
        
    def defB(self):
        self.b = "B"
    @defB    
    def printB(self):
        print self.b
    
f = foo()
f.printB()

f1 = bar()
f1.printB()