code: def gmean_norm(data):
      in_data = data > np.mean(data) * 0.8
      gmean = np.mean(data[in_data])
      return data / gmean
  
file_path: nibabel/nibabel/tests/data/check_parrec_reslice.py
imports: import glob
  import numpy
  import numpy.linalg
  import nibabel
  from nibabel import parrec
  from nibabel.affines import to_matvec
  from nibabel.optpkg import optional_package
label_desc: Use image node_id 2 for calling a global function with example usage: gmean_norm(data) and returns: unknown