code: def visualization_type(self) -> str:
      return "real"
  
imports: import unittest
  from typing import Callable, List, Union
  import torch
  import torch.nn
  from captum.insights import AttributionVisualizer, Batch
  from captum.insights.attr_vis.app import FilterConfig
  from captum.insights.attr_vis.features import BaseFeature, FeatureOutput, ImageFeature
  from tests.helpers.basic import BaseTest
label_desc: Use image node_id 2 for calling the RealFeature obj's underlying member method code with example usage: obj.visualization_type() and returns: str