def METHOD_NAME():
    # Check that blue theme is not listed in available themes
    themes = available_themes()
    assert 'test_blue' not in themes
    # Create new blue theme based on dark theme
    blue_theme = get_theme('dark').to_rgb_dict()
    blue_theme.update(
        background='rgb(28, 31, 48)',
        foreground='rgb(45, 52, 71)',
        primary='rgb(80, 88, 108)',
        current='rgb(184, 112, 0)',
    )
    # Register blue theme
    register_theme('test_blue', blue_theme, "test")
    # Check that blue theme is listed in available themes
    themes = available_themes()
    assert 'test_blue' in themes
    # Check that the dark theme has not been overwritten
    dark_theme = get_theme('dark').to_rgb_dict()
    assert dark_theme['background'] != blue_theme['background']
    # Check that blue theme can be gotten from available themes
    theme = get_theme('test_blue').to_rgb_dict()
    assert theme['background'] == blue_theme['background']
    theme = get_theme("test_blue")
    assert theme.background.as_rgb() == blue_theme["background"]