这段代码有什么问题？setValue行出错

import arcpy

fc = r"C:\Users\songwk.songwk-PC2.000\Documents\ArcGIS\Default.gdb\GX_DSL_Intersect"

with arcpy.da.UpdateCursor(fc, ["SHAPE@","SX","SY","EX","EY"]) as cursor:

    for row in cursor:

        #print("QD:X = {0},Y = {1}",row[0].firstPoint.X,row[0].firstPoint.Y)

        #print("ZD:X = {0},Y = {1}",row[0].lastPoint.X,row[0].lastPoint.Y)

        row.setValue("SX",row[0].firstPoint.Y)

        row.setValue("SY",row[0].firstPoint.Y)

        row.setValue("EX",row[0].lastPoint.X)

        row.setValue("EY",row[0].lastPoint.Y)

        cursor.updateRow(row)

    del cursor, row