python私有方法和變量

class aa(object):
	def __init__(self):
		self.x = 12
		self.__z = 13
	def printx(self):
		print 'in a'
		print self.x
		print self.__z
	def pp(self):
		print '++++++++++++++++++'
	def __px(self):
		print '0000000000000000000'
class bb(aa):
	def __init__(self):
		#aa.__init__(self)
		super(bb,self).__init__()
		self.y = 14
	def printy(self):
		self.p()
		print 'in b'
		print self.y
		#print self.__z
		self.p()
	def p(self):
		super(bb, self).pp()
		print '--------------------'
b = bb()
b.printy()
b.printx()
#b.__px()