code: def get_form_prefix(self, step=None, form=None):
          
          if step is None:
              step = self.steps.current
          return str(step)
docs: Returns the prefix which will be used when calling the actual form for
          the given step. `step` contains the step-name, `form` the form which
          will be called with the returned prefix.
  
          If no step is given, the form_prefix will determine the current step
          automatically.