WDT Watchdog timer code

Hi MartinL,
Thanks for your detailed information in your posts.
I am trying to implement your code on my SAMD21 however the code won't compile for me.
I am getting the following error;

'WDT_CONFIG_PER_7' was not declared in this scope

If I comment out the following line it compiles but I have not tried to program it into a board yet.

REG_WDT_CONFIG = WDT_CONFIG_PER_7;                // Set the WDT reset timeout to 1 second

Can you provide any advice please?