AWS Lambda function to create Thing and attach policy to thing certificate

Test Event
{
  "thing_name": "myThingNew",
  "access_key": "AKIAXLU4V3LTW4PS6CCH",
  "secret_key": "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",
  "policy_name": "ESP32_Test_Policy",
  "certificate_arn": "arn:aws:iot:us-east-1:506060987111:cert/f1020e6ed117a7c2834f25fc3025f54d6ff5b7662d339c6d4367937a2a0d135d"
}

lambda_function.py 
import boto3

def lambda_handler(event, context):
    thing_name = event['thing_name']
    access_key = event['access_key']
    secret_key = event['secret_key']
    policy_name= event['policy_name']
    certificate_arn = event['certificate_arn']
    
    session = boto3.Session(
        aws_access_key_id=access_key,
        aws_secret_access_key=secret_key
    )
    
    iot_client = session.client('iot')
    response = iot_client.create_thing(
        thingName=thing_name
    )
    thing_arn = response['thingArn']
    #certificate = iot_client.create_keys_and_certificate(
    #    setAsActive=True
    #)
    
    # Get the certificate ARN and ID
    #  certificate_arn = certificate['certificateArn']
    # certificate_id = certificate['certificateId']
    
    # Attach the policy to the certificate
    iot_client.attach_policy(
        policyName=policy_name,
        target=certificate_arn
    )
    # Attach the certificate to the thing
    iot_client.attach_thing_principal(
        thingName=thing_name,
        principal=certificate_arn
    )
    
    return {
        'statusCode': 200,
        'body': f"Successfully created IoT thing: {thing_name}"
    }