python代码实现arcgis标注某要素的某字段

困扰我好几天的属性字段标注用python代码表示今天终于解决了，和大家分享一下下！！！！

mxd=arcpy.mapping.MapDocument("current")
for lyr in arcpy.mapping.ListLayers(mxd):
    if lyr.name == "要素图层名称":
        lyr.showLabels = True
        for lblClass in lyr.labelClasses:
            lblClass.showClassLabels = True
            lblClass.expression = "[字段名称]"