__init__  实例化对象,__init__并不相当于C#中的构造函数,执行它的时候,实例已构造出来了。

class Node:
 def __init__(self, value):
    self._value = value
    self._children = []

# Example
if __name__ == '__main__':
  root = Node(0)
  print root
  print type(root)

C:\Python27\python.exe C:/Users/TLCB/PycharmProjects/untitled/mycompany/Django/a31.py
<__main__.Node instance at 0x01C5BDF0>
<type 'instance'>