code: def run(self, msg):
      print(f"B: message from A: {msg}")
  
file_path: pytorch-lightning/docs/source-app/levels/intermediate/scripts/two_comms_non_ml.py
imports: from lightning.app import LightningWork, LightningFlow, LightningApp
  import time
label_desc: Use image node_id 1 for calling the B obj's underlying member method code with example usage: obj.run(msg) without return types