在python中从子类调用父类构造函数

因此，如果我有课：

 class Person(object):
'''A class with several methods that revolve around a person's Name and Age.'''

    def __init__(self, name = 'Jane Doe', year = 2012):
        '''The default constructor for the Person class.'''
        self.n = name
        self.y = year

然后这个子类：

 class Instructor(Person):
'''A subclass of the Person class, overloads the constructor with a new parameter.'''
     def __init__(self, name, year, degree):
         Person.__init__(self, name, year)

我有点失去了对如何让子类来调用和使用父类的构造函数name和year，同时加入了新的参数degree在子类。