WordPress notices errors | from Login Form Template

We added php files to the child theme folder based on this link recommendations:

However, we are getting PHP notices:
Undefined variable: logged_in_message
Undefined variable: logout_redirect
Undefined variable: logged_in_avatar

Let us know what we are missing?

Thank you,

Oxana

Actually, we had to define these 3 variables in that registration file and the errors are gone.