How to tell if my AWS account "owns" a given IP address in Python boto
Here's the method I have come up with:
To look up all IPs to see if they are EIPs associated with our AWS account

Get a list of all our EIPs
Get a list of all instances
Build list of all public IPs of instances
Merge lists/use same list
Check desired IPs against this list.

Comments welcome.
So I have a list of public IP addresses and I'd like to see if they are a public IP that is associated with our account.  I know that I can simply paste each IP into the search box in the AWS EC2 console.  However I would like to automate this process via a Python program.
I'm told anything you can do in the console, you can do via CLI/program, but which function do I use to simply either return a result or not, based on whether it's a public IP that's associated with our account?
I understand I may have to do two searches, one of instances (which would cover non-EIP public IPs) and one of EIPs (which would cover disassociated EIPs that we still have).  
But how?