求助，安装了Pyinsane不知道怎么调用，希望大佬给个简单实例

import pyinsane.abstract as pyinsane
device = pyinsane.get_devices()[0]
device.opti**['resolution'].value = 1200
device.opti**['mode'].value = 'Color'
device.opti**['source'].value = 'Transparency Unit'
# Beware: Some scanner have "Lineart" or "Gray" as default mode
device.opti**['mode'].value = 'Color'
scan_instance = device.scan(multiple=False)
try:
    while True:
        scan_instance.read()
except EOFError:
    pass
image = scan_instance.get_img()这个会提示AssertionError