Python obj ref

#!/usr/bin/env python

class Foo(object):
	def __init__(self, arg):
		self.arg = arg

	def __repr__(self):
		return 'Foo({})'.format(self.arg)
		

class Bar(object):
	def __init__(self, arg):
		self.arg = arg

	def __repr__(self):
		return 'Bar({})'.format(self.arg)		


foo = Foo(1)

bar1 = Bar(foo)	
bar2 = Bar(foo)

print(bar1, bar2)  # Bar(Foo(1)), Bar(Foo(1))
bar1.arg.arg = 2
print(bar1, bar2)  # Bar(Foo(2)), Bar(Foo(2))