获取字典的特定索引

我有这个lambda函数

def lambda_handler(event, context):
    response = client.describe_maintenance_windows(
Filters=[
    {
        'Key': 'Name',
        'Values': [
            'test',
        ]
    },
],
)
MWId = response["WindowIdentities"]
return(MWId)

我得到了以下响应响应结构

[
  {
    "WindowId": "mw-0154acefa2151234",
    "Name": "test",
    "Enabled": true,
    "Duration": 4,
    "Cutoff": 0,
    "Schedule": "cron(0 0 11 ? * SUN#4 *)",
    "NextExecutionTime": "2024-08-25T11:00Z"
  }
] 

如何获取WindowId的值,以便将其传递给变量?我尝试了以下操作,但收到“errorMessage”:“'list'对象不可调用”

mwidvalue = MWId("WindowId")