diff --git a/internal/identifier/id.go b/internal/identifier/id.go
index e5888a9..c08bbcf 100644
--- a/internal/identifier/id.go
+++ b/internal/identifier/id.go
@@ -41,3 +41,6 @@ func (i ID) Extension() (exttype string, fileext string) {
 	return exttype, fileext
 }
 
+func (i ID) IsEmpty() bool {
+	return i == ""
+}