# File lib/fog/aws/models/elasticache/security_group.rb, line 39
        def revoke_ec2_group(group_name, group_owner_id=owner_id)
          requires :id
          requires :owner_id if group_owner_id.nil?
          data = connection.revoke_cache_security_group_ingress(
            id, group_name, group_owner_id
          )
          merge_attributes(data.body['CacheSecurityGroup'])
        end