From Nii to dicom

ROOT_DIR_GMCHALLENGE = "/gdrive/My Drive/DAIR RESOURCES/PyTorch/medical_imaging/train/"
mri_input_filename = os.path.join(ROOT_DIR_GMCHALLENGE,
                                          'site1-sc01-image.nii.gz')
mri_gt_filename = os.path.join(ROOT_DIR_GMCHALLENGE,
                                       'site1-sc01-mask-r1.nii.gz')

pair = mt_datasets.SegmentationPair2D(mri_input_filename, mri_gt_filename)
slice_pair = pair.get_pair_slice(0)
input_slice = slice_pair["input"]
gt_slice = slice_pair["gt"]

img = input_slice
plt.imshow(img)
plt.show()

i want to try the code above on dicom images , any idea what to change to make it work on dicom format ?