diff --git a/projects/angular-l10n/src/lib/pipes/l10n-translate.pipe.ts b/projects/angular-l10n/src/lib/pipes/l10n-translate.pipe.ts
index a76ec80..609577a 100644
--- a/projects/angular-l10n/src/lib/pipes/l10n-translate.pipe.ts
+++ b/projects/angular-l10n/src/lib/pipes/l10n-translate.pipe.ts
@@ -15,6 +15,7 @@ export class L10nTranslatePipe implements PipeTransform {
     public transform(key: null, language: string, params?: any): null;
     public transform(key: "", language: string, params?: any): null;
     public transform(key: string, language: string, params?: any): string;
+    public transform(key: any, language: string, params?: any): string | null;
     public transform(key: any, language: string, params?: any): string | null {
         if (key == null || key === '') return null;
 
@@ -33,6 +34,7 @@ export class L10nTranslateAsyncPipe extends L10nAsyncPipe implements PipeTransfo
     public transform(key: null, params?: any, language?: string): null;
     public transform(key: "", params?: any, language?: string): null;
     public transform(key: string, params?: any, language?: string): string;
+    public transform(key: any, params?: any, language?: string): string | null;
     public transform(key: any, params?: any, language?: string): string | null {
         if (key == null || key === '') return null;