Add code source blocks to the chapter Graph.

Fix "函数" and "方法"

codes/python/chapter_array_and_linkedlist/my_list.py

@@ -10,7 +10,7 @@ from include import *
 
 """ 列表类简易实现 """
 class MyList:
-    """ 构造函数 """
+    """ 构造方法 """
     def __init__(self):
         self.__capacity = 10                 # 列表容量
         self.__nums = [0] * self.__capacity  # 数组（存储列表元素）

codes/python/chapter_tree/avl_tree.py

@@ -89,7 +89,7 @@ class AVLTree:
         self.root = self.__insert_helper(self.root, val)
         return self.root
 
-    """ 递归插入结点（辅助函数）"""
+    """ 递归插入结点（辅助方法）"""
     def __insert_helper(self, node: Optional[TreeNode], val: int) -> TreeNode:
         if node is None:
             return TreeNode(val)
@@ -111,7 +111,7 @@ class AVLTree:
         root = self.__remove_helper(self.root, val)
         return root
 
-    """ 递归删除结点（辅助函数） """
+    """ 递归删除结点（辅助方法） """
     def __remove_helper(self, node: Optional[TreeNode], val: int) -> Optional[TreeNode]:
         if node is None:
             return None