old_contents: import pytest
  import webview
  from .util import destroy_window, run_test
  
  def bg_color():
      import webview
      destroy_window(webview)
      webview.create_window('Background color test', 'https://www.example.org', background_color='#0000FF')
  
  
  def test_bg_color():
      run_test(bg_color)
  
new_contents: import pytest
  from .util import destroy_window, run_test
  
  def bg_color():
      import webview
      destroy_window(webview)
      webview.create_window('Background color test', 'https://www.example.org', background_color='#0000FF')
  
  
  def invalid_bg_color():
      import webview
  
      with pytest.raises(ValueError):
          webview.create_window('Background color test', 'https://www.example.org', background_color='#dsg0000FF')
  
      with pytest.raises(ValueError):
          webview.create_window('Background color test', 'https://www.example.org', background_color='FF00FF')
  
      with pytest.raises(ValueError):
          webview.create_window('Background color test', 'https://www.example.org', background_color='#ac')
  
      with pytest.raises(ValueError):
          webview.create_window('Background color test', 'https://www.example.org', background_color='#EFEFEH')
  
      with pytest.raises(ValueError):
          webview.create_window('Background color test', 'https://www.example.org', background_color='#0000000')
  
  
  def test_bg_color():
      run_test(bg_color)
  
  
  def test_invalid_bg_color():
      run_test(invalid_bg_color)
  
subject: Add invalid bg_color test cases