code: def _transform(self, data, transform, step_size):
      '''
      Transform the data. If the transform is not supported by this series,
      returns the data unaltered.
      '''
      if callable(transform):
        data = transform(data, step_size)
      return datf _transform(self, data, transform, step_size):
      '''
      Transform the data. If the transform is not supported by this series,
      returns the data unaltered.
      '''
      if callable(transform):
        data = transform(data, step_size)
      return data
docs: Transform the data. If the transform is not supported by this series,
      returns the data unaltered.