anchor.diff:      [<Test>]
       let ``Multiply multiplies`` () =
           let result = 
  -            [Push 4; Push 2; Multipy]
  +            [Push 4; Push 2; Multiply]
               |> Stack.fold Stack.initialState
           Assert.AreEqual(List.head result, 8)    
   
  
positive.code:         let result = 
              [Push 4; Print]
              |> Stack.fold Stack.initialState
          Assert.AreEqual(List.head result, 4)
negative.code: open NUnit.Framework
  open StackVM
  
  module Instructions =
  
      [<Test>]
      let ``Push 4 pushes 4 on the stack`` () =
  