              self.extra_data_key: {},
          }
  
      def reset(self):
          self.init_data()
  
      def _get_current_step(self):
          return self.data[self.step_key]
  
 
</s> remove     Please remember to take care of removing old files as the
    :class:`WizardView` won't remove any files, whether the wizard gets
    finished correctly or not.
 </s> add     Please remember to take care of removing old temporary files, as the
    :class:`WizardView` will only remove these files if the wizard finishes
    correctly.
        # Delete temporary files before breaking reference to them.
        wizard_files = self.data[self.step_files_key]
        for step_files in six.itervalues(wizard_files):
            for step_file in six.itervalues(step_files):
                self.file_storage.delete(step_file['tmp_name'])
              self.extra_data_key: {},
          }
  
      def reset(self):
        # Delete temporary files before breaking reference to them.
        wizard_files = self.data[self.step_files_key]
        for step_files in six.itervalues(wizard_files):
            for step_file in six.itervalues(step_files):
                self.file_storage.delete(step_file['tmp_name'])
          self.init_data()
  
      def _get_current_step(self):
          return self.data[self.step_key]
  
keep keep keep add keep keep keep keep keep
 Fixed #22299 -- Cleanup wizard temp files when possible.

Thanks to @erikr for the review. 
django/contrib/formtools/wizard/storage/base.py