code: def __setitem__(self, k, v):
      from lightning.app.core import LightningFlow, LightningWork
  
      if not isinstance(k, str):
          raise Exception("The provided key should be an string")
  
      if isinstance(k, str) and "." in k:
          raise Exception(
              f"The provided name {k} contains . which is forbidden."
          )
  
      _set_child_name(self, v, k)
      if self._backend:
          if isinstance(v, LightningFlow):
              LightningFlow._attach_backend(v, self._backend)
          elif isinstance(v, LightningWork):
              self._backend._wrap_run_method(
                  _LightningAppRef().get_current(), v
              )
      v._name = f"{self.name}.{k}"
      super().__setitem__(k, v)
  
file_path: pytorch-lightning/src/lightning/app/structures/dict.py
imports: import typing
  from lightning.app.utilities.app_helpers import _LightningAppRef, _set_child_name
label_desc: Use image node_id 2 for calling the Dict obj's underlying member method code with example usage: obj.__setitem__(k, v) without return types