    # 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