code: def nonzero(x: NdarrayOrTensor) -> NdarrayOrTensor:
      """`np.nonzero` with equivalent implementation for torch.
  
      Args:
          x: array/tensor.
  
      Returns:
          Index unravelled for given shape
      """
      if isinstance(x, np.ndarray):
          return np.nonzero(x)[0]
      return torch.nonzero(x).flatten()
  
imports: from __future__ import annotations
  from collections.abc import Sequence
  from typing import TypeVar
  import numpy
  import torch
  from monai.config.type_definitions import NdarrayOrTensor, NdarrayTensor
  from monai.utils.misc import is_module_ver_at_least
  from monai.utils.type_conversion import convert_data_type, convert_to_dst_type
label_desc: Use image node_id 9 for calling a global function with example usage: nonzero(x) and returns: torch, np