arcpy进行栅格计算或者归一化时保存时都会出现如下错误？不知道是什么原因引起。

# -*- coding: UTF-8 -*-
import arcpy
# from arcpy.gp import *
from arcpy.sa import *

arcpy.CheckOutExtension("spatial")

arcpy.env.workspace = "E:/data_test/data/"

for i in range(2018,2021):
    raster01 = Raster("{}_ndvi.tif".format(i)) * 0.6
    raster02 = Raster("{}_sm.tif".format(i)) * 0.4
    raster = raster01 + raster02
    outname = "E:/data_test/com_result/a{}.tif".format(i)
    raster.save(outname)
    print "第{}张处理完毕".format(i-2017)

将outname = "E:/data_test/com_result/a{}.tif".format(i)改为outname = r"E:/data_test/com_result/a{}.tif".format(i)试试