Dynamically modifying "__setattr__"

  I wanted to postpone the introduction of a custom __setattr__
  to a point later at runtime where I then wanted to use
  "self.__setattr__ = self.setattr" to set this attribute. But this
  did not have the effect desired to print "setattr called" as can
  be seen below.

  main.py

class A:
    def __init__( self ):
        self.__setattr__ = self.setattr
    def setattr( self, key, value ):
        print( 'setattr called.' )

a = A()
a.x = 1

  transcript

  Any idea how to achieve something like this?