python - forward and back command -

wanted to know how to write a forward and back command in a superclass, but I found out that If this is true (or wrong) some help plz

  def forward (self): Returns (self .100) def back (self): return (self.50)   

  def forward (self): self.position + = self.distance return (self.position) Def back (self): self.position - = self.distance return (self.position)  

Edit: I assume that you install the app Some are doing something like progress bar, where some operations progress progress (copy files), and if the user cancels other operations, then rollback (delete files) to ask the appropriate questions as the comments of other users.