Any lambda/python gurus who can help?

[Too Late]

Hi all
I am getting an issue when returning a list of users and their accesskeys which are over X number of days old.
I am lead to believe its truncated and i need to use boto/python paginator

I am really struggling to implement this into my lambda. Is anyone able to help?
Thank

     import boto3, json, time, datetime, sys, pprint

sns = boto3.client('sns')
usernames = []
mylist = []

sts_client = boto3.client('sts')
assumed_role_object=sts_client.assume_role(
    RoleArn="arn:aws:iam::11111111:role/lambda_role",
    RoleSessionName="AssumedRoleSession4"
)
credentials=assumed_role_object['Credentials']
client=boto3.client(
    'iam',
    aws_access_key_id=credentials['AccessKeyId'],
    aws_secret_access_key=credentials['SecretAccessKey'],
    aws_session_token=credentials['SessionToken'],
    )

def lambda_handler(event, context):
    users = client.list_users()
    for key in users['Users']:
        a = str(key['UserName'])
        usernames.append(a)
    for username in usernames:
        try:
            res = client.list_access_keys(UserName=username)
            accesskeydate = res['AccessKeyMetadata'][0]['CreateDate']
            accesskeydate = accesskeydate.strftime("%Y-%m-%d %H:%M:%S")
            currentdate = time.strftime("%Y-%m-%d %H:%M:%S", time.gmtime())
            accesskeyd = time.mktime(datetime.datetime.strptime(accesskeydate, "%Y-%m-%d %H:%M:%S").timetuple())
            currentd = time.mktime(datetime.datetime.strptime(currentdate, "%Y-%m-%d %H:%M:%S").timetuple())
            active_days = (currentd - accesskeyd)/60/60/24 ### We get the data in seconds. converting it to days

            if 90 < active_days:
                a = str(username)
                c = int(int(round(active_days)))

                mylist.append(a)
                mylist.append(c)
        except:
                f = str('')

    print(mylist)
    finallist = ''.join(str(mylist))
    finallist = finallist

    sns_message = (finallist)
    response = sns.publish(
        TopicArn='arn:aws:sns:eu-west-2:111111:sns',
        Message= sns_message,
        Subject='Access Keys which need rotating',
    ) 

[Ynox]

Your script looks vaguely reasonable at a glance.

Probably stating the obvious, but I found the boto3 docs to be fairly reasonable and Google had decent examples last time I was doing some Python scripting for AWS.

What part do you think requires pagination? The keys?