向列表分配输入时出现问题

我知道这可能是一个简单的问题,但是在查看了python 2.6.4的文档之后,我似乎找不到问题所在。这是我的全部文件。我遇到的问题是在get_phone_number()中。在询问了电话号码数量后,我得到了以下错误:

Traceback (most recent call last):
  File "/home/charles/workspace/HelloWorld/hello.py", line 27, in <module>
    c.get_phone_number()
  File "/home/charles/workspace/HelloWorld/hello.py", line 17, in get_phone_number
    self.phone_number[phone_count]
AttributeError: Contact instance has no attribute 'phone_number'

我似乎能够动态地定义一个属性,但如果它是一个列表,就不能定义它了?请帮助!

class Name():
        def get_name(self):
            self.first = raw_input("First Name?\n")
            self.middle = raw_input("Middle Name?\n")
            self.last = raw_input("Last Name?\n")
        pass
    class Address():
        def get_address(self):
            self.street = raw_input("Street?\n")
            self.city = raw_input("City?\n")
            self.zip = raw_input("Zip Code?\n")
        pass
    class Phone_Number():
        def get_phone_number(self):
            count = 0
            phone_count = raw_input("How many phone numbers?\n")
            self.phone_number[phone_count]
            while count < (phone_count - 1):
                self.phone_number[phone_count] = raw_input("Phone Number: ")
                phone_count -= 1
        pass
    class Contact(Name, Address, Phone_Number):
        pass
    c = Contact()
    c.get_name()
    c.get_address()
    c.get_phone_number()