code: def test_theme_enable(alt, basic_spec):
      active_theme = alt.themes.active
  
      try:
          alt.themes.enable("none")
  
          chart = alt.Chart.from_dict(basic_spec)
          dct = chart.to_dict()
  
          # schema should be in the top level
          assert dct.pop("$schema").startswith("http")
  
          # remainder of spec should match the basic spec
          # without any theme settings
          assert dct == basic_spec
      finally:
          # reset the theme to its initial value
          alt.themes.enable(active_theme)
  
file_path: altair/tests/vegalite/test_common.py
imports: import pytest
  import pandas
  from altair.vegalite import v5
label_desc: Use image node_id 6 for calling a global function with example usage: test_theme_enable(alt, basic_spec) without return types