code: def save_gray_tiff(array: np.ndarray, filename: str):
      """
      Save numpy array into a TIFF file
  
      Args:
          array: numpy ndarray with any shape
          filename: the filename to be used for the tiff file.
      """
      img_gray = array
      imwrite(filename, img_gray, shape=img_gray.shape)
  
      return filename
  
imports: from __future__ import annotations
  import os
  import unittest
  from typing import Any
  from unittest import skipUnless
  import numpy
  import torch
  from parameterized import parameterized
  from monai.config import PathLike
  from monai.data import DataLoader, Dataset
  from monai.data.wsi_reader import WSIReader
  from monai.transforms import Compose, LoadImaged, ToTensord
  from monai.utils import first, optional_import
  from monai.utils.enums import PostFix, WSIPatchKeys
  from tests.utils import assert_allclose, download_url_or_skip_test, skip_if_no_cuda, testing_data_config
label_desc: Use image node_id 2 for calling a global function with example usage: save_gray_tiff(array, filename) and returns: filename