diff --git a/docs/CustomAuthenticationProvider.md b/docs/CustomAuthenticationProvider.md
index 0b590b130..625adf944 100644
--- a/docs/CustomAuthenticationProvider.md
+++ b/docs/CustomAuthenticationProvider.md
@@ -18,7 +18,7 @@ class MyAuthenticationProvider implements AuthenticationProvider {
 	 * This should return a Promise that resolves to an accessToken (in case of success) or rejects with error (in case of failure)
 	 * Basically this method will contain the implementation for getting and refreshing accessTokens
 	 */
-	public async getAccessToken(): Promise<any> {}
+	public async getAccessToken(): Promise<string> {}
 }
 ```