diff --git a/rw_core/mocks/adapter.go b/rw_core/mocks/adapter.go
index 28d06da..63474ef 100644
--- a/rw_core/mocks/adapter.go
+++ b/rw_core/mocks/adapter.go
@@ -249,3 +249,8 @@
 func (ta *Adapter) Disable_port(deviceId string, port *voltha.Port) error { //nolint
 	return nil
 }
+
+// Child_device_lost -
+func (ta *Adapter) Child_device_lost(pDeviceID string, pPortNo uint32, onuID uint32) error { //nolint
+	return nil
+}