def quickExample(testfolder=None):
    """
    Example of how to run a Radiance routine for a simple rooftop bifacial system

    """
    import bifacial_radiance
    if testfolder == None:
        testfolder = bifacial_radiance.main._interactive_directory(title=
            'Select or create an empty directory for the Radiance tree')
    demo = bifacial_radiance.RadianceObj('simple_panel', path=testfolder)
    demo.setGround(0.62)
    try:
        epwfile = demo.getEPW(37.5, -77.6)
    except ConnectionError:
        pass
    metdata = demo.readEPW(epwfile)
    cumulativeSky = True
    if cumulativeSky:
        demo.genCumSky(demo.epwfile)
    else:
        demo.gendaylit(metdata, 4020)
    moduletype = 'test'
    moduleDict = demo.makeModule(name=moduletype, x=1.59, y=0.95)
    sceneDict = {'tilt': 10, 'pitch': 1.5, 'clearance_height': 0.2,
        'azimuth': 180, 'nMods': 20, 'nRows': 7}
    scene = demo.makeScene(moduletype=moduletype, sceneDict=sceneDict)
    octfile = demo.makeOct(demo.getfilelist())
    analysis = bifacial_radiance.AnalysisObj(octfile, demo.name)
    frontscan, backscan = analysis.moduleAnalysis(scene, sensorsy=9)
    analysis.analysis(octfile, demo.name, frontscan, backscan)
    print('Annual bifacial ratio average:  %0.3f' % (sum(analysis.Wm2Back) /
        sum(analysis.Wm2Front)))
    return analysis
