Filtering Value List in ArcGIS Pro ModelBuilder?

[AyokunleAdebisi1]

I am creating a model tool which is 95% complete but I want the tool to be able to select a category from the value list of categories and only all the classes that belong to that category shows to which one can select from. For instance of we have a group like this; Continent: Africa, Europe, Asia . Country: Nigeria, Ghana,Kenya, Egypt, Germany,Italy, Albania, Japan, China, Indonesia. By selecting Africa in that continent category, automatically gives you only options of country that belongs to that continent.

Please I really need an urgent answer for me to know if it is possible and how?.  Thanks

[AyokunleAdebisi]

using python script, how do I dynamically generate the choicelist such that if i pick Africa from the continent the Country field will only populate that which found in Africa.I think this will will set in the validation in script. please I need an example of what the script will look like to be able to perform that task. Thanks