Add google recaptcha on memberpress login’s form

Hello,
I’ve been using memberpress plugin and it provides a good login page.
Now i wanted to know how i can add a google recaptcha on this login form and what i find out is that page: https://www.axew3.com/w3/2018/11/add-recaptcha-to-memberpress-login-page/
Unfortunately, the version of the plugin is too old and the code has changed, so it doesn’t work anymore (you can’t find the sgr_check’s function in the code).
Is there a way to do the same thing with the actual version of code ? And if yes, how ?
Thanks you.

The page I need help with: [log in to see the link]