In reply to jimmyhuang0904:
Your module my_tb only needs to import uvm_pkg and my_test_pkg.
You have not shown all you parameter overrides correctly. That is critical to get matching overrides.
class new_class #(type T = apples, type VI = some_if) extend class_to_override#(T,V);
And you did not show the creation. The parameter types need to be shown there as well
mon = class_to_override#(T,V)::type_id::create("mon",this);
Do the parameters in the override match the parameters of the override?