code: def test_volume_property_diffuse(vol_prop):
      assert isinstance(vol_prop.diffuse, float)
      value = 0.45
      vol_prop.diffuse = value
      assert vol_prop.diffuse == value
  
file_path: pyvista/tests/plotting/test_volume_property.py
imports: import pytest
  import pyvista
  from pyvista.plotting.volume_property import VolumeProperty
label_desc: Use image node_id 7 for calling a global function with example usage: test_volume_property_diffuse(vol_prop) without return types