diff --git a/lib/snippets/copyright/index.ts b/lib/snippets/copyright/index.ts
index 11e1d4c..a18c8bd 100644
--- a/lib/snippets/copyright/index.ts
+++ b/lib/snippets/copyright/index.ts
@@ -36,7 +36,7 @@ export default class Copyright implements Snippet {
       this.fix_file_license.bind (this)
     );
 
-    modify_json ((json) => {
+    await modify_json ((json) => {
       json.author = `${options.author} <${options.email}>`;
       json.license = options.has_license
         ? options.license