diff --git a/src/tree.py b/src/tree.py
index 7a18dd22448a0d30309b4ace87c785307271393d..0c58d32b0da0e7099c2d2804fc97cdc35b240e28 100644
--- a/src/tree.py
+++ b/src/tree.py
@@ -7,7 +7,6 @@ import sys
 import uuid
 import re
 
-
 id_set = set()
 logger = logging.getLogger(__name__)
 logger.setLevel(logging.INFO)
@@ -16,6 +15,7 @@ formatter = logging.Formatter('%(asctime)s - %(levelname)s - %(message)s')
 handler.setFormatter(formatter)
 logger.addHandler(handler)
 
+
 def search_author(author_dict, username):
     for key in author_dict:
         names = author_dict[key]
@@ -23,6 +23,7 @@ def search_author(author_dict, username):
             return key
     return username
 
+
 def user_name(md_file, author_dict):
     ret = subprocess.Popen([
         "git", "log", md_file
@@ -35,8 +36,9 @@ def user_name(md_file, author_dict):
     author_nick_name = author_lines[-1]
     return search_author(author_dict, author_nick_name)
 
+
 def load_json(p):
-    with open(p, 'r') as f:
+    with open(p, 'r', encoding="utf-8") as f:
         return json.loads(f.read())
 
 
@@ -92,13 +94,13 @@ def check_export(base, cfg):
 
 class TreeWalker:
     def __init__(
-        self, root,
-        tree_name,
-        title=None,
-        log=None,
-        authors=None,
-        enable_notebook=None,
-        ignore_keywords=False
+            self, root,
+            tree_name,
+            title=None,
+            log=None,
+            authors=None,
+            enable_notebook=None,
+            ignore_keywords=False
     ):
         self.ignore_keywords = ignore_keywords
         self.authors = authors if authors else {}