Refactoring lab4
Refactoring lab4

lionell/labs,lionell/labs,lionell/university-labs,lionell/labs,lionell/labs,lionell/labs,lionell/university-labs,lionell/laboratories,lionell/laboratories,lionell/university-labs,lionell/university-labs,lionell/labs,lionell/labs,lionell/labs,lionell/laboratories,lionell/labs,lionell/labs,lionell/labs