code: def get_changes(self, factory_name, global_factory=False, resources=None,
                      task_handle=taskhandle.NullTaskHandle()):
          
          if resources is None:
              resources = self.project.get_python_files()
          changes = ChangeSet('Introduce factory method <%s>' % factory_name)
          job_set = task_handle.create_jobset('Collecting Changes',
                                              len(resources))
          self._change_module(resources, changes, factory_name,
                              global_factory, job_set)
          return changes
docs: Get the changes this refactoring makes
  
          `factory_name` indicates the name of the factory function to
          be added.  If `global_factory` is `True` the factory will be
          global otherwise a static method is added to the class.
  
          `resources` can be a list of `rope.base.resource.File`\s that
          this refactoring should be applied on; if `None` all python
          files in the project are searched.