maya python set motionblur

from mtoa.core import createOptions

def set_motion_blur(switch):
    mtoa.core.createOptions()
    if switch == "on":
        cmds.setAttr("defaultArnoldRenderOptions.motion_blur_enable", 1)
        cmds.setAttr("defaultArnoldRenderOptions.ignoreMotionBlur" ,1)
        cmds.setAttr("defaultArnoldRenderOptions.range_type", 0)
        cmds.setAttr("defaultArnoldRenderOptions.motion_frames" ,1)
    elif switch == "off":        
        cmds.setAttr("defaultArnoldRenderOptions.motion_blur_enable", 0)
        cmds.setAttr("defaultArnoldRenderOptions.ignoreMotionBlur" ,0)
        cmds.setAttr("defaultArnoldRenderOptions.range_type", 1)
        cmds.setAttr("defaultArnoldRenderOptions.motion_frames" ,0.5)
        
set_motion_blur("on")