code: def _clean_labels_ar(X, labels):
      X = X.astype(labels.dtype)
      labels = np.ravel(labels)
      labels[labels == 0] = X
      return labels
  
file_path: nilearn/nilearn/_utils/segmentation.py
imports: import warnings
  import numpy
  from scipy import ndimage, sparse
  from scipy.sparse.linalg import cg
  from sklearn.utils import as_float_array
label_desc: Use image node_id 5 for calling a global function with example usage: _clean_labels_ar(X, labels) and returns: labels