Parsing JSON in AWS Lambda Python

For a personal project I'm trying to write an AWS Lambda in Python3.9 that will delete a newly created user, if the creator is not myself. For this, the logs in CloudWatch Logs will trigger (via CloudTrail and EventBridge) my Lambda. Therefore, I will receive the JSON request as my event in :

def lambdaHandler(event, context)

But I have trouble to parse it...

If I print the event, I get that :

{'version': '1.0', 'invokingEvent': '{
        "configurationItemDiff": {
            "changedProperties": {},
            "changeType": "CREATE"
        },
        "configurationItem": {
            "relatedEvents": [],
            "relationships": [],
            "configuration": {
                "path": "/",
                "userName": "newUser",
                "userId": "xxx",
                "arn": "xxx",
                "createDate": "2022-11-23T09:02:49.000Z",
                "userPolicyList": [],
                "groupList": [],
                "attachedManagedPolicies": [],
                "permissionsBoundary": null,
                "tags": []
            },
            "supplementaryConfiguration": {},
            "tags": {},
            "configurationItemVersion": "1.3",
            "configurationItemCaptureTime": "2022-11-23T09:04:40.659Z",
            "configurationStateId": 1669194280659,
            "awsAccountId": "141372946428",
            "configurationItemStatus": "ResourceDiscovered",
            "resourceType": "AWS::IAM::User",
            "resourceId": "xxx",
            "resourceName": "newUser",
            "ARN": "arn:aws:iam::xxx:user/newUser",
            "awsRegion": "global",
            "availabilityZone": "Not Applicable",
            "configurationStateMd5Hash": "",
            "resourceCreationTime": "2022-11-23T09:02:49.000Z"
        },
        "notificationCreationTime": "2022-11-23T09:04:41.317Z",
        "messageType": "ConfigurationItemChangeNotification",
        "recordVersion": "1.3"
    }', 'ruleParameters': '{
        "badUser": "arn:aws:iam::xxx:user/badUser"
    }', 'resultToken': 'xxx=', 'eventLeftScope': False, 'executionRoleArn': 'arn:aws:iam: : xxx:role/aws-service-role/config.amazonaws.com/AWSServiceRoleForConfig', 'configRuleArn': 'arn:aws:config:eu-west-1: xxx:config-rule/config-rule-q3nmvt', 'configRuleName': 'UserCreatedRule', 'configRuleId': 'config-rule-q3nmvt', 'accountId': 'xxx'
}

And for my purpose, I'd like to get the "changeType": "CREATE" value to say that if it is CREATE, I check the creator and if it is not myself, I delete newUser.

So the weird thing is that I copy/paste that event into VSCode and format it in a .json document and it says that there are errors (line 1 : version and invokingEvent should be double quote for example, but well).

For now I only try to reach and print the

"changeType": "CREATE"

by doing :

import json
import boto3
import logging

iam = boto3.client('iam')

def lambda_handler(event, context):
    """
    Triggered if a user is created
    Check the creator - if not myself :
    - delete new user and remove from groups if necessary
    """
    
    try:
        print(event['invokingEvent']["configurationItemDiff"]["changeType"])
    except Exception as e:
        print("Error because :")
        print(e)

And get the error string indices must be integers - it happens for ["configurationItemDiff"]. I understand the error already (I'm new to python though so maybe not completely) and tried many things like :

• print(event['invokingEvent']['configurationItemDiff']) : swapping double quote by simple quote but doesnt change anything
• print(event['invokingEvent'][0]) : but it gives me the index { and [2] gives me the c not the whole value.

At this point I'm stuck and need help because I can't find any solution on this. I don't use SNS, maybe should I ? Because I saw that with it, the JSON document would not be the same and we can access through ["Records"][...] ? I don't know, please help