diff --git a/sysprop/sysprop_library.go b/sysprop/sysprop_library.go
index 6a53414..93a3fe0 100644
--- a/sysprop/sysprop_library.go
+++ b/sysprop/sysprop_library.go
@@ -322,6 +322,9 @@
 		}}
 }
 
+var _ android.ApexModule = (*syspropLibrary)(nil)
+
+// Implements android.ApexModule
 func (m *syspropLibrary) ShouldSupportSdkVersion(ctx android.BaseModuleContext,
 	sdkVersion android.ApiLevel) error {
 	return fmt.Errorf("sysprop_library is not supposed to be part of apex modules")