After reading the information of a training school, I wrote a case in it.

#enconding = "utf-8"
  class Home :
      def __init__ ( self , area):
          self.area = area
          self.containsItem = []
      def __str__ ( self ): 
        msg = "The current available area of ​​the house is:" + str ( self .area)
          if len ( self .containsItem ) > 0 : 
            msg += "The items contained are: " + ", ". join ( self .containsItem )
          returnmsg

    def addItem（self ， item）：
         self .area  -  = item.getMianji（）
         self .containsItem.append（item.getName（））


class bed :
      def __init__ ( self , name , mianji ):
          self .__mianji=mianjiself
          .__ name=name
      def __str__ ( self ):
          return "%s The area of ​​the bed is: %d" %( self.getName () , self.self.getMianji ())
      def getMianji ( self ):
          return self .__mianji
      def getName ( self ):
          return self . __name

bed1 = bed( "simmons" , 4 ) bed2 = 
bed ( "hammock" , 2 ) 
fang1 = home( 20 )
  print (fang1) 
fang1.addItem(bed1) print ( fang1) 
fang1.addItem(bed2) print (fang1 ) )

class Digua ():
      def __init__ ( self ):
          self .cookedLevel = 0
  self .cookedString = "raw"
  self .condiments = []
      def __str__ ( self ):
          return "The rawness of this sweet potato is: %s, taste is %s flavor' %( self.cookedString , "" .join(self.condiments))
      def cook ( self , time):
          self.cookedLevel +=
          time if 0 < self                .cookedLevel <= 3：
             self .cookedString = “生的”
 elif 3 < self .cookedLevel <= 5：
             self .cookedString = “半生不熟”
 elif 5 < self .cookedLevel <= 8：
             self .cookedString = “烤好了”
 elif self .cookedLevel> 8：
             self .cookedString = “木炭了”
 else：
             self .cookedString = “生的”
def kouwei（                                    自我， *参数）：
         自 .condiments.extend（参数）

digua1 = Digua（）
digua1.cook（1）
digua1.kouwei（“番茄” ，“沙拉”）
 print（digua1）

digua1.cook（5）
digua1.kouwei（“酱油” ，“香菜”）
 print（digua1）