Fix a small bug

- Fix a bug that the clients under v4.0.0 cannot upload the cloud save

.github/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,42 @@
+---
+name: Bug report
+about: Create a report to help us improve
+title: ''
+labels: bug
+assignees: ''
+
+---
+
+<!-- Please use a clear and concise title 能不能来个正常点的标题 -->
+<!-- English or Chinese is ok 中英皆可 -->
+
+**Describe the bug 问题描述**
+A clear and concise description of what the bug is.
+
+**To Reproduce 复现过程**
+Steps to reproduce the behavior:
+1. Go to '...'
+2. Click on '....'
+3. Scroll down to '....'
+4. See error
+
+**Error log 报错日志**
+<!-- Including logs, texts in CMD, some messages in some softwares... -->
+```
+[Error] Balabalabalabala...
+```
+
+**Screenshots 截图**
+<!-- Well, if you have error logs, pictures are optional. It is too slow for me to open a picture. -->
+<!-- 有错误日志就别放图了，网速有多慢你懂的 -->
+If applicable, add screenshots to help explain your problem.
+
+**Environment 环境**
+ - Server OS: [e.g. Windows 11 Beta]
+ - Client OS: [e.g. Android 10]
+ - Server Version: [e.g. v2.8.1]
+ - Client Version [e.g. 4.0.256c]
+ - Others like python version, flask version, some proxy softwares if you used...
+
+**Additional context 附加内容**
+Add any other context about the problem here.

.github/ISSUE_TEMPLATE/feature_request.md

@@ -0,0 +1,20 @@
+---
+name: Feature request
+about: Suggest an idea for this project
+title: ''
+labels: enhancement
+assignees: ''
+
+---
+
+**Is your feature request related to a problem? Please describe.**
+A clear and concise description of what the problem is. Ex. I'm always frustrated when [...]
+
+**Describe the solution you'd like**
+A clear and concise description of what you want to happen.
+
+**Describe alternatives you've considered**
+A clear and concise description of any alternative solutions or features you've considered.
+
+**Additional context**
+Add any other context or screenshots about the feature request here.

.github/ISSUE_TEMPLATE/q-a.md

@@ -0,0 +1,14 @@
+---
+name: Q&A
+about: Ask a question or wonder something
+title: ''
+labels: Q&A
+assignees: ''
+
+---
+
+**What you want to know 你想知道什么**
+Clearly describe your question here.
+
+**Additional context 附加内容**
+Add anything other here. Your abilities or knowledge base, your contact information, some pictures...

latest version/core/save.py

@@ -110,6 +110,8 @@ class SaveData:
         '''
             从Arcaea客户端给的奇怪字符串中获取存档数据，并进行数据校验
         '''
+        if not value:
+            return None
         if key not in self.__dict__:
             raise KeyError(
                 'Property `%s` is not found in the instance of `SaveData` class.' % key)

latest version/server/user.py

@@ -138,7 +138,7 @@ def cloud_post(user_id):
         save.set_value(
             'story_data', request.form['story_data'], request.form['story_checksum'])
         save.set_value(
-            'finalestate_data', request.form['finalestate_data'], request.form['finalestate_checksum'])
+            'finalestate_data', request.form.get('finalestate_data'), request.form.get('finalestate_checksum'))
 
         save.update_all(user)
         return success_return({'user_id': user.user_id})