How AWS config can help to trace the unused resources like security group, volumes etc if we are using the lambda for ARN and passing the code to it.

hi, i am trying to make a setup where AWS Config will be used to create a rule and ARN used here will be of lambda, inside lambda we kept the code to fetch the security group which are not used or any other logic for volumes. i have used the IAM-ROLE in which describe.ec2.instance, and security group is also attached. now, i don't know how it will work as when i clicked on the re-evaluate section of the AWS Config then it is not returning any thing, however i intentially created the 2 security group which are not associated with anything. waiting for your complete response with code of lambda too. thanks