code: def mapper(sphere):
      sphere["array"] = sphere.points[:, 2]
      pl = pv.Plotter()
      actor = pl.add_points(sphere, style="points_gaussian")
      return actor.mapper
  
file_path: pyvista/tests/plotting/mappers/test_gaussian_mapper.py
imports: import pytest
  import pyvista
  from pyvista.plotting.mapper import PointGaussianMapper
label_desc: Use image node_id 1 for calling a global function with example usage: mapper(sphere) and returns: actor