diff --git a/packages/core/__tests__/core.test.ts b/packages/core/__tests__/core.test.ts
index 2cef4790..bf35f152 100644
--- a/packages/core/__tests__/core.test.ts
+++ b/packages/core/__tests__/core.test.ts
@@ -2,7 +2,7 @@ import * as fs from 'fs'
 import * as os from 'os'
 import * as path from 'path'
 import * as core from '../src/core'
-import { HttpClient } from '@actions/http-client'
+import {HttpClient} from '@actions/http-client'
 import {toCommandProperties} from '../src/utils'
 
 
diff --git a/packages/core/src/core.ts b/packages/core/src/core.ts
index f03b577e..7f509968 100644
--- a/packages/core/src/core.ts
+++ b/packages/core/src/core.ts
@@ -351,6 +351,6 @@ export function getState(name: string): string {
   return process.env[`STATE_${name}`] || ''
 }
 
-export async function getIDToken(aud: string | undefined = undefined): Promise<string> {
+export async function getIDToken(aud?: string | undefined): Promise<string> {
   return await OidcClient.getIDToken(aud)
 }
\ No newline at end of file