Need groovy script to generate access token instead of Auth profile

I am able to generate access token for a given username and password from POSTMAN by giving below details.

Auth type as "OAuth 2.0", Grant type as "Authorization Code" and also other details like clientId,client secret, authorization url, access token url , redirect url, scope and audience.

When clicked on "Get new access token" after entering all the detail, a login web page will be displayed and username&password will be entered.Then access token will be generated.

The access token can be generated using auth profile in auth manager in Ready API.

But I need to generate it using groovy script.

Can someone please help me in getting it.