Python design patterns of the combination pattern principle and usage examples of analysis

#!/usr/bin/env python
# -*- coding:utf-8 -*-
__author__ = 'Andy'
"""
big talk about design patterns
design pattern——Combined mode
Combined mode(Composite Pattern):Combine objects into a tree structure to represent the“portion-synthesis”hierarchy,Combined mode使得用户对单个对象和组合对象的使用具有一致性.
"""
# Abstract an organization class
class Component(object):
  def __init__(self, name):
     = name
  def add(self,comp):
    pass
  def remove(self,comp):
    pass
  def display(self, depth):
    pass
# Leaf nodes
class Leaf(Component):
  def add(self,comp):
    print 'Cannot add subordinate nodes'
  def remove(self,comp):
    print 'Cannot delete subordinate nodes'
  def display(self, depth):
    strtemp = ''
    for i in range(depth):
      strtemp += strtemp+'-'
    print strtemp+
# Branches
class Composite(Component):
  def __init__(self, name):
     = name
     = []
  def add(self,comp):
    (comp)
  def remove(self,comp):
    (comp)
  def display(self, depth):
    strtemp = ''
    for i in range(depth):
      strtemp += strtemp+'-'
    print strtemp+
    for comp in :
      (depth+2)
if __name__ == "__main__":
  # Generate tree roots
  root = Composite("root")
  #2 leaves growing on the root
  (Leaf('leaf A'))
  (Leaf('leaf B'))
  # Branches growing from roots Composite X
  comp = Composite("Composite X")
  (Leaf('leaf XA'))
  (Leaf('leaf XB'))
  (comp)
  # Branches growing from roots Composite X
  comp2 = Composite("Composite XY")
  #Composite X grows 2 leaves
  (Leaf('leaf XYA'))
  (Leaf('leaf XYB'))
  (comp2)
  # Two more leaves grew from the root, C and D. D didn't open up and fell off. #
  (Leaf('Leaf C'))
  leaf = Leaf("Leaf D")
  (leaf)
  (leaf)
  # Showcase Organization
  (1)