Format python codes with black. (#453)

codes/python/chapter_tree/binary_tree_bfs.py

@@ -5,24 +5,26 @@ Author: a16su (lpluls001@gmail.com)
 """
 
 import sys, os.path as osp
+
 sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
 from modules import *
 from collections import deque
 
+
 def level_order(root: TreeNode | None) -> list[int]:
-    """ 层序遍历 """
+    """层序遍历"""
     # 初始化队列，加入根节点
     queue: deque[TreeNode] = deque()
     queue.append(root)
     # 初始化一个列表，用于保存遍历序列
     res: list[int] = []
     while queue:
-        node: TreeNode = queue.popleft() # 队列出队
-        res.append(node.val)             # 保存节点值
+        node: TreeNode = queue.popleft()  # 队列出队
+        res.append(node.val)  # 保存节点值
         if node.left is not None:
-            queue.append(node.left)      # 左子节点入队
+            queue.append(node.left)  # 左子节点入队
         if node.right is not None:
-            queue.append(node.right)     # 右子节点入队
+            queue.append(node.right)  # 右子节点入队
     return res