code: def __init__(self, file):
      super().__init__(
          "Stage name not provided."
          f"Please specify the name as: `{file.relpath}:stage_name`"
      )
  
imports: from dvc.exceptions import DvcException
label_desc: Use image node_id 1 to create a new StageNameUnspecified object from inherited base classes: DvcException with example: obj = StageNameUnspecified(file)