class A:
    def printf(*args):
        print(args)
def printff(*args):
    print(args)

a=A()
a.printf()
print ('-'*5,a.printf)
print ('-'*5,A.printf)

A.printf=printff
a.printf()
print ('-'*5,a.printf)
print ('-'*5,A.printf)

a.printf=printff
a.printf()
print ('-'*5,a.printf)
print ('-'*5,A.printf)

A.printf=printff
a.printf()
print ('-'*5,a.printf)
print ('-'*5,A.printf)

##Output
##(<__main__.A object at 0x7b3b140e80>,)
##----- <bound method A.printf of <__main__.A object at 0x7b3b140e80>>
##----- <function A.printf at 0x7b3b148048>
##(<__main__.A object at 0x7b3b140e80>,)
##----- <bound method printff of <__main__.A object at 0x7b3b140e80>>
##----- <function printff at 0x7b3b2fce18>
##()
##----- <function printff at 0x7b3b2fce18>
##----- <function printff at 0x7b3b2fce18>
##()
##----- <function printff at 0x7b3b2fce18>
##----- <function printff at 0x7b3b2fce18>

class A:
    # here you are defining a method for class A which is <function A.printf at 0x7b3b148048>
    def printf(*args):
        print(args)
# here you are defining a function which is <function printff at 0x7b3b2fce18>
def printff(*args):
    print(args)

a=A() # here when you create an instance of your object you have <bound method A.printf of <__main__.A object at 0x7b3b140e80>>
a.printf()
print ('-'*5,a.printf)
print ('-'*5,A.printf)

A.printf=printff # here you are setting <function A.printf at 0x7b3b148048> = <function printff at 0x7b3b2fce18>
a.printf()
print ('-'*5,a.printf)
print ('-'*5,A.printf)

a.printf=printff # here <bound method A.printf of <__main__.A object at 0x7b3b140e80>> = <function printff at 0x7b3b2fce18>
a.printf()
print ('-'*5,a.printf)
print ('-'*5,A.printf)

A.printf=printff # here <function printff at 0x7b3b2fce18> = <function printff at 0x7b3b2fce18>
a.printf()
print ('-'*5,a.printf)
print ('-'*5,A.printf)