2055：失去与“ localhost：3306”处的MySQL服务器的连接，系统错误：连接不可用

Question

当我尝试运行代码时，出现此错误：

File "script.py", line 36, in <module>
    result  = cursor.execute(sql_insert_query)
  File "/home/rexio18/.local/lib/python2.7/site-packages/mysql/connector/cursor_cext.py", line 266, in execute
    raw_as_string=self._raw_as_string)
  File "/home/rexio18/.local/lib/python2.7/site-packages/mysql/connector/connection_cext.py", line 405, in cmd_query
    errno=2055, values=(addr, 'Connection not available.'))
mysql.connector.errors.OperationalError: 2055: Lost connection to MySQL server at 'localhost:3306', system error: Connection not available.

代码：

for child in root:
    for element in child:
        for subelement in element:
            a = subelement.attrib['currency']
            b = subelement.text
            connection = mysql.connector.connect(host ='localhost', user ='root', passwd ='admin' , database ='python')
                    cursor = connection.cursor()
            sql_insert_query = "INSERT INTO valoare(moneda, flux) VALUES (%s, %s)",(a, b)
            result  = cursor.execute(sql_insert_query)
            connection.commit()