Added "Fixed Cards", i.e. predefined values for cards, so you can define in a lesson the set of operations you want to test your student on.
You define this in the lesson file by adding:
fixed_card=(val1,val2,op)...
Exemple:
fixed_card_list=(1,1,+)(1,1,-)(20,20,+)(50,30,+)

Very primitive checkings so be careful with space and so on.
Additionally remove COMPRENSIVE (set it to 0) and RANDOMIZE