class_docstr: A context manager to change the default tensor type when tensors get created.
  
  See: :func:`torch.set_default_dtype`
code: def __exit__(
      self, exc_type: Any, exc_value: Any, traceback: Any
  ) -> None:
      torch.set_default_dtype(self._previous_dtype)
  
file_path: pytorch-lightning/src/lightning/fabric/plugins/precision/utils.py
imports: from typing import Any, Mapping, Type, Union
  import torch
  from torch import Tensor
label_desc: Use image node_id 3 for calling the _DtypeContextManager obj's underlying member method code with example usage: obj.__exit__(exc_type, exc_value, traceback) without return types