Update the structure of the chapter

of binary tree.

codes/python/chapter_stack_and_queue/array_stack.py

@@ -34,11 +34,6 @@ class ArrayStack:
     def peek(self):
         assert not self.is_empty(), "栈为空"
         return self.__stack[-1]
-
-    """ 访问索引 index 处元素 """
-    def get(self, index):
-        assert index < self.size(), "索引越界"
-        return self.__stack[index]
     
     """ 返回列表用于打印 """
     def to_list(self):
@@ -62,10 +57,6 @@ if __name__ == "__main__":
     peek = stack.peek()
     print("栈顶元素 peek =", peek)
 
-    """ 访问索引 index 处元素 """
-    num = stack.get(3)
-    print("栈索引 3 处的元素为 num =", num)
-
     """ 元素出栈 """
     pop = stack.pop()
     print("出栈元素 pop =", pop)