title: Modifying rules for a given EC2 security group with Boto3
body: <p>I have recently been working on programatically adding and removing ingress rules to security groups on my EC2 server. However, I now seem to have hit a bit of a wall. </p>
  
  <p>I would like to be able to modify existing rules through a python script, but I haven't been able to find any guidance on the Boto3 docs.</p>
  
  <p>Is there any way in which this can be done?</p>
  
  <p>Thanks</p>