我想要使用Python来连接MySQL数据库，但是报了如下错误
File "/usr/local/lib/python3.5/dist-packages/pymysql/__init__.py", line 94, in Connect
return Connection(*args, **kwargs)
File "/usr/local/lib/python3.5/dist-packages/pymysql/connections.py", line 325, in __init__
self.connect()
File "/usr/local/lib/python3.5/dist-packages/pymysql/connections.py", line 599, in connect
self._request_authentication()
File "/usr/local/lib/python3.5/dist-packages/pymysql/connections.py", line 861, in _request_authentication
auth_packet = self._read_packet()
File "/usr/local/lib/python3.5/dist-packages/pymysql/connections.py", line 684, in _read_packet
packet.check_error()
File "/usr/local/lib/python3.5/dist-packages/pymysql/protocol.py", line 220, in check_error
err.raise_mysql_exception(self._data)
File "/usr/local/lib/python3.5/dist-packages/pymysql/err.py", line 109, in raise_mysql_exception
raise errorclass(errno, errval)
pymysql.err.InternalError: (1049, "Unknown database 'expert'")
百度结果均告知为未创建相应的数据库导致本错误，但是我已经创建了expert数据库，但仍然提示数据库不存在。
此外，本服务器下的数据库均能正常连接。
这是我的数据库连接代码：
config = {
'host': cf.get("mySql", "host"),
'port': int(cf.get("mySql", "port")),
'user': cf.get("mySql", "user"),
'password': cf.get("mySql", "password"),
'db': cf.get("mySql", "db"),
'charset': cf.get("mySql", "charset")
}
table_to_save = cf.get("mySql", "save_table")
try:
con = pymysql.connect(**config)
except Exception:
con = Exception
log_info = "Connection to MySQL has been rejected"
print(log_info)
os._exit(0)
配置文件为：
[mySql]
host=127.0.0.1
port=3306
user=root
password=123456
db=expert
charset=utf8
有大佬可以帮忙解决一下吗？