关于SendModelingCommand官方例子执行不成功的原因

import c4d
from c4d import utils


def main():
    settings = c4d.BaseContainer()                 # Settings2
    settings[c4d.MDATA_EXTRUDE_OFFSET] = 50.0      # Length of the extrusion
    
    res = utils.SendModelingCommand(command = c4d.ID_MODELING_EXTRUDE_TOOL,
                                    list = [op.GetObject()],
                                    mode = c4d.MODELINGCOMMANDMODE_POLYGONSELECTION,
                                    bc = settings,
                                    doc = doc)
    c4d.EventAdd()
    
    if res is False:
        print "Something went wrong."
    elif res is True:
        print "Command successfull."
    elif isinstance(res, list):
        print "Here you get the newly created object(s)."