diff --git a/src/async-function.ts b/src/async-function.ts
index bb018d3..54fd74d 100644
--- a/src/async-function.ts
+++ b/src/async-function.ts
@@ -1,12 +1,10 @@
-type AsyncFunction<A, R> = (args: A) => Promise<R>
-
 export async function callAsyncFunction<A = {}, R = unknown>(
   args: A,
   source: string
 ): Promise<R> {
   const argsKeys = Object.keys(args).join(',')
 
-  const wrappedFunction: AsyncFunction<A, R> = eval(`async({${argsKeys}}) => {
+  const wrappedFunction: (args: A) => Promise<R> = eval(`async({${argsKeys}}) => {
     ${source}
   }`)