title: Loop on if-statement to reject invalid input
body: <p>In python is there a way to redo a raw input and if statement if the answer is invalid?</p>
  
  <p>So for instance if you ask the user to guess 1 or 2, and they guess 3 you create the additional elif or else to tell the user that the answer is invalid and go through the raw input / if statement again?</p>