Remove layer assertion error

Question

I am using below code to remove any layer if it has zero features in it.

mxd = arcpy.mapping.MapDocument("CURRENT")
aDF = mxd.activeDataFrame
namE = ["No_Work_Done"]
if int(arcpy.GetCount_management(namE[0])[0]) < 1:
    try:
        arcpy.mapping.RemoveLayer(aDF, namE[0])
    except Exception as d:
        print(d.message)
    else:
        print("No Work Done or Conflict Present in Data\n")

However this is returning run-time error and assertion error as below

Runtime error 
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "c:\program files (x86)\arcgis\desktop10.3\arcpy\arcpy\utils.py", line 182, in fn_
    return fn(*args, **kw)
  File "c:\program files (x86)\arcgis\desktop10.3\arcpy\arcpy\mapping.py", line 1845, in RemoveLayer
    assert isinstance(remove_layer, Layer)
AssertionError

What could be the problem here?

Answer 1

namE[0] is a string. RemoveLayer method expects a Layer instance. You need to get Layerinstance of layer "No_Work_Done". You should use arcpy.mapping.ListLayers method. This method gives you list of layers as a list of Layer instances, not as a list of strings. When you change the script as follows, the layer will be removed.

mxd = arcpy.mapping.MapDocument("CURRENT")
aDF = mxd.activeDataFrame
namE = ["No_Work_Done"]
if int(arcpy.GetCount_management(namE[0])[0]) < 1:
    try:
        # ADD/CHANGE FOLLOWING TWO LINES
        REMOVE = arcpy.mapping.ListLayers(aDF, namE[0])[0]
        arcpy.mapping.RemoveLayer(aDF, REMOVE)
    except Exception as d:
        print(d.message)
    else:
        print("No Work Done or Conflict Present in Data\n")

You may be wondering why you don't get error when using GetCount_management with namE[0]. Because that method accepts a layer as a string, but RemoveLayer doesn't.