how to copy layer and add to same mxd and rename layer using ArcPy and ArcMap 10.2?

Question

I am trying to copy a layer in an mxd and add that layer to the bottom of the TOC using Python, but I have not found a way to save the mxd programatically without making a copy. I also haven't found how to rename the copied layer. Here is my code: it runs with no errors but the copied layer is not added to the mxd when I open it.

import arcpy
import arcpy.mapping


mxd = arcpy.mapping.MapDocument(r"D:/arcgisserver/directories/my_mxd.mxd")
df = arcpy.mapping.ListDataFrames(mxd, "Layers")[0]
print "df : " + df.name
addLayer = arcpy.mapping.ListLayers(mxd, "", df)[0]
print "layer ? : " + addLayer.name

arcpy.mapping.AddLayer(df, addLayer, "BOTTOM")

# Refresh things
arcpy.RefreshActiveView()
arcpy.RefreshTOC()
del mxd, df, addLayer

Answer 1

After adding the layer to the in-memory mxd, you should save the mxd using:

mxd.save()

or

mxd.saveACopy (r"D:/arcgisserver/directories/my_mxd2.mxd")

to change the layer name, simply change the name property of the layer:

addLayer.name = "NewLayerName"

Update: To rename the newly added layer you should make a reference to the layer first:

allLayers= arcpy.mapping.ListLayers(mxd, "", df)
copiedLayer = allLayers[len(allLayers)-1]  //because it is added to the bottom of TOC
copiedLayer.name = "NewLayerName"