Python 实现数据结构-堆栈和队列的操作方法

class Queue():
 def __init__(self):
 self.__list = list()

 def isEmpty(self):
 return self.__list == []

def push(self, data):
 self.__list.append(data)

 def pop(self):
 if self.isEmpty():
  return False
 return self.__list.pop(0)

 def __len__(self):
 return len(self.__list)
 def __str__(self):
 if self.isEmpty():
  return ''
 return ' '.join([str(x) for x in self.__list])

class Stack():
 def __init__(self):
 self.__list = list()

 def isEmpty(self):
 return self.__list == []

 def push(self, data):
 self.__list.append(data)
 
 def pop(self):
 if self.isEmpty():
  return False
 return self.__list.pop()

 def __len__(self):
 return len(self.__list)

 def __str__(self):
 if self.isEmpty():
  return ''
 return ' '.join([str(x) for x in self.__list])