code: def test_anti_aliasing_ssaa(default_theme):
      # default should is not enabled
      if default_theme.anti_aliasing != "ssaa":
          pl = pv.Plotter(theme=default_theme)
          assert "vtkSSAAPass" not in pl.renderer._render_passes._passes
  
      default_theme.anti_aliasing = "ssaa"
      assert default_theme.anti_aliasing == "ssaa"
      pl = pv.Plotter(theme=default_theme)
      assert "vtkSSAAPass" in pl.renderer._render_passes._passes
  
imports: import os
  import pytest
  import vtk
  import pyvista
  from pyvista import colors
  from pyvista.examples.downloads import download_file
  from pyvista.plotting.themes import DarkTheme, Theme, _set_plot_theme_from_env
  from pyvista.plotting.utilities.gl_checks import uses_egl
label_desc: Use image node_id 48 for calling a global function with example usage: test_anti_aliasing_ssaa(default_theme) without return types