code: def initialize(cls):
      if StableDiffusionRunner._instance is None:
          print("Initializing StableDiffusionRunner...")
          StableDiffusionRunner._instance = cls()
      return StableDiffusionRunner._instance
  
imports: from typing import ClassVar, Optional
  import torch
  import os
  from bigdl.nano.pytorch import InferenceOptimizer
  from diffusers.schedulers import *
  from .utils import get_snapshot_dir_from_model_version
  from .pipelines import NanoStableDiffusionPipeline
label_desc: Use image node_id 5 for calling the StableDiffusionRunner obj's underlying member method code with example usage: obj.initialize(cls) and returns: StableDiffusionRunner