刚开始学用Django搭建环境，已经初始化了本地数据库，但是执行Python manage.py runserver语句报错，现在不知道怎么改了
报错语句如下：
System check identified no issues (0 silenced).
Unhandled exception in thread started by <function check_errors..wrapper at 0x00000204AA203268>
Traceback (most recent call last):
File "E:\python3_env\bk_demo\lib\site-packages\django\utils\autoreload.py", line 227, in wrapper
fn(*args, **kwargs)
File "E:\python3_env\bk_demo\lib\site-packages\django\core\management\commands\runserver.py", line 128, in inner_run
self.check_migrations()
File "E:\python3_env\bk_demo\lib\site-packages\django\core\management\base.py", line 422, in check_migrations
executor = MigrationExecutor(connections[DEFAULT_DB_ALIAS])
File "E:\python3_env\bk_demo\lib\site-packages\django\db\migrations\executor.py", line 20, in init
self.loader = MigrationLoader(self.connection)
File "E:\python3_env\bk_demo\lib\site-packages\django\db\migrations\loader.py", line 52, in init
self.build_graph()
File "E:\python3_env\bk_demo\lib\site-packages\django\db\migrations\loader.py", line 209, in build_graph
self.applied_migrations = recorder.applied_migrations()
File "E:\python3_env\bk_demo\lib\site-packages\django\db\migrations\recorder.py", line 65, in applied_migrations
self.ensure_schema()
File "E:\python3_env\bk_demo\lib\site-packages\django\db\migrations\recorder.py", line 52, in ensure_schema
if self.Migration._meta.db_table in self.connection.introspection.table_names(self.connection.cursor()):
File "E:\python3_env\bk_demo\lib\site-packages\django\db\backends\base\base.py", line 254, in cursor
return self._cursor()
File "E:\python3_env\bk_demo\lib\site-packages\django\db\backends\base\base.py", line 229, in _cursor
self.ensure_connection()
File "E:\python3_env\bk_demo\lib\site-packages\django\db\backends\base\base.py", line 213, in ensure_connection
self.connect()
self.connect()
File "E:\python3_env\bk_demo\lib\site-packages\pymysql\connections.py", line 850, in connect
self._get_server_information()
File "E:\python3_env\bk_demo\lib\site-packages\pymysql\connections.py", line 1085, in _get_server_information
self.server_charset = charset_by_id(lang).name
File "E:\python3_env\bk_demo\lib\site-packages\pymysql\charset.py", line 34, in by_id
return self._by_id[id]
KeyError: 255
求指点
