\item \self 
Consider the following script. What are the outputs of the 
two calls to \texttt{solver.check()}? Explain your answers.
In particular, elaborate the difference of using an \texttt{Int()} and a \texttt{BitVec()} for the variables. 

  \vskip7em

  \begin{pythonSourceCode}
      from z3 import *

      solver = Solver()

      intX = Int("intX")
      bvX  = BitVec("bvX", 2)

      solver.push()
      solver.add(bvX + 1 < bvX - 1)
      result = solver.check()
      print(result)
      if result == sat:
          print(solver.model())
      solver.pop()

      solver.push()
      solver.add(intX + 1 < intX - 1)
      result = solver.check()
      print(result)
      if result == sat:
          print(solver.model())
  \end{pythonSourceCode}
