Python (ArcPy) - gdb2TOC - Importing file geodatabase (GDB) to table of contents (TOC) of ArcMap?

I have a geodatabase with several feature dataset and feature classes associated with it respectively. I would like to create a .mxd where the Table of contents consist of group layer and each group layer has several shapefile. The group layer name should be same as Feature dataset name.The feature classes in each feature dataset comes shapefiles with in that particular group layer as shown in figure.

 import os,arcpy

gdb=r'I:\python\GroupLayer\ABC.gdb'
template_mxd = r'I:\python\GroupLayer\empty.mxd'
template_group_layer = r'I:\python\GroupLayer\empty_group.lyr'
output_mxd = r'I:\python\GroupLayer\not_empty.mxd'

mxd=arcpy.mapping.MapDocument(template_mxd)
df = arcpy.mapping.ListDataFrames(mxd)[0]
groups={}
for path, dirs, files in arcpy.da.Walk(gdb):
    #Any "folder" in a GDB is a Feature Dataset
    #and there can only be a single level
    for d in dirs:
        #Add an empty group layer to ArcMap
        lyr=arcpy.mapping.Layer(template_group_layer)
        lyr.name=d
        arcpy.mapping.AddLayer(df,lyr)
        groups[d]=arcpy.mapping.ListLayers(mxd,d,df)[0]

    for f in files:
        fp=os.path.join(path,f)
        dsc=arcpy.Describe(fp)
        lyr=None
        view=None
        if dsc.dataType == 'FeatureClass':
            lyr=arcpy.management.MakeFeatureLayer(fp)[0]
        elif dsc.dataType == 'RasterDataset':
            lyr=arcpy.management.MakeRasterLayer(fp)[0]
        elif dsc.dataType == 'Table':
            view=arcpy.management.MakeTableView(fp)[0]
        else:continue

        if path==gdb and lyr:
            lyr.visible=False
            arcpy.mapping.AddLayer(df,lyr)
        elif view:
            arcpy.mapping.AddTableView(df, view)
        else:
            d=os.path.basename(path)
            arcpy.mapping.AddLayerToGroup(df, groups[d], lyr, "BOTTOM")

mxd.saveACopy(output_mxd)


The result in TOC will be...