code: def slice_z_center(mesh):
      """Slice mesh through center in z normal direction, move to z=0."""
      slice_mesh = mesh.slice(normal="z")
      slice_mesh.translate((0, 0, -slice_mesh.center[-1]), inplace=True)
      return slice_mesh
  
label_desc: Use image node_id 1 for calling a global function with example usage: slice_z_center(mesh) and returns: slice_mesh