def _find_usage_network_interfaces(self):
        """find usage of network interfaces"""
        enis = paginate_dict(
            self.conn.describe_network_interfaces,
            alc_marker_path=['NextToken'],
            alc_data_path=['NetworkInterfaces'],
            alc_marker_param='NextToken'
        )

        self.limits['Network interfaces per Region']._add_current_usage(
            len(enis['NetworkInterfaces']),
            aws_type='AWS::EC2::NetworkInterface'
        )