code: def add_head(renderer, points, color, opacity=0.95):
      renderer.mesh(
          *points.T, triangles=seghead_tri, color=color, opacity=opacity
      )
  
imports: import nibabel
  import numpy
  from scipy import linalg
  import mne
  from mne.io.constants import FIFF
label_desc: Use image node_id 1 for calling a global function with example usage: add_head(renderer, points, color, opacity) without return types