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？