diff --git a/index.d.ts b/index.d.ts
index 4b745a9..9b1b634 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -254,7 +254,8 @@ export interface IRange {
 
 export interface IUtils {
     /** converts an array of arrays of JS data to a worksheet. */
-	aoa_to_sheet<T>(data:Array, opts?:any);
+    aoa_to_sheet(data: <T>, opts?:any): IWorkSheet;
+
     /** Converts a worksheet object to an array of JSON objects */
     sheet_to_json<T>(worksheet:IWorkSheet, opts?: {
         raw?: boolean;