Python 使用Google Adword API时，获取此错误运算符error.OPERATOR_不支持@operations[0]

我在使用ManagedCustomerService时出错。我想更新帐户标签和mutateLabel（）为帐户分配标签和删除标签这两个操作都已成功完成，但在更新帐户标签时不支持运算符。\u这是我的完整代码

from googleads import adwords
COSTOMER_ID = 'xxxxxxxxxx'
LABEL_ID = 'xxxxxxxxxx'

adwords_client = adwords.AdWordsClient.LoadFromStorage('googleads.yaml')
manage_customer_service = adwords_client.GetService('ManagedCustomerService', version='v201809')

operations = [
    {
        "operator": "SET",
        "operand": {
            "labelId": LABEL_ID,
            "customerId": COSTOMER_ID
        }
    }
]
try:
    response = manage_customer_service.mutateLabel(operations)
    print(response)
except Exception as e:
    print('Exception accrued:')
    print(e)