code: def test_nans_threshold_maps_ratio(maps, affine_eye):
      data = get_data(maps)
      data[:, :, 0] = np.nan
  
      maps_img = Nifti1Image(data, affine_eye)
      _threshold_maps_ratio(maps_img, threshold=0.8)
  
imports: import numpy
  import pytest
  from nibabel import Nifti1Image
  from scipy.ndimage import label
  from nilearn._utils.data_gen import generate_labeled_regions, generate_maps
  from nilearn._utils.exceptions import DimensionError
  from nilearn.conftest import _affine_eye, _img_4d_zeros, _shape_3d_default
  from nilearn.image import get_data
  from nilearn.regions import RegionExtractor, connected_label_regions, connected_regions
  from nilearn.regions.region_extractor import _remove_small_regions, _threshold_maps_ratio
label_desc: Use image node_id 7 for calling a global function with example usage: test_nans_threshold_maps_ratio(maps, affine_eye) without return types