find usage for ACLs

def _find_usage_ACLs(self):
        """find usage for ACLs"""
        # Network ACLs per VPC
        acls = defaultdict(int)
        for acl in self.conn.describe_network_acls()['NetworkAcls']:
            acls[acl['VpcId']] += 1
            # Rules per network ACL
            self.limits['Rules per network ACL']._add_current_usage(
                len(acl['Entries']),
                aws_type='AWS::EC2::NetworkAcl',
                resource_id=acl['NetworkAclId']
            )
        for vpc_id in acls:
            self.limits['Network ACLs per VPC']._add_current_usage(
                acls[vpc_id],
                aws_type='AWS::EC2::VPC',
                resource_id=vpc_id,
            )