"""
Python does polymorphism
"""
class A:                           # base class declartion
	def __init__( self ):      # constructor
		self.index = 0     # define and initialize variable

	def doIncrement( self ):   # manipulator
		self.index += 1

class B( A ):                      # subclass declaration
	def doIncrement( self ):   # function replacement
		self.index += 3

class C( A ):                      # another subclass
	def doIncrement( self ):
		self.index += 7
	
a = A()
a.doIncrement()
print( "a index %d" % ( a.index ) )

b = B()
b.doIncrement()
print( "b index %d" % ( b.index ) )

c = C()
c.doIncrement()
print( "c index %d" % ( c.index ) )