Undefined index: class in bootstrap_barrio_preprocess_input()

Hi,

Since a the recent 4.16 release (updated to me from 4.9, but after some check this bug affect only 4.16 release) ; I have following two notice on my login page (custom template ; bootstrap_barrio subtheme) :

Notice: Undefined index: class in bootstrap_barrio_preprocess_input() (line 485 of themes/contrib/bootstrap_barrio/bootstrap_barrio.theme).

Notice: Undefined index: class in bootstrap_barrio_preprocess_input() (line 490 of themes/contrib/bootstrap_barrio/bootstrap_barrio.theme).

In bootstrap_barrio_preprocess_input() there is no check that class array key exists ; with this simple check my errors would disappear.
After debugging this function, I see that the error (notice) appear on each input of type hidden which doesn't have any class by default. Ex : form_id hidden input

Can you update this function ?

BR