How do I properly use UpdateLayer to change symbology for layer?

Kevin_C

I am trying to change the symbology of a layer in a map document using arcpy. I have a reference layer I am using. Please see the following code:

mxd = arcpy.mapping.MapDocument("CURRENT")
df = arcpy.mapping.ListDataFrames(mxd)[0]
nuristanGeol = arcpy.mapping.Layer(r"C:\GeolAfghanProvince.gdb\Nuristan_geology")
afgGeol = arcpy.mapping.Layer(r"C:\afgeolmap.lyr")
arcpy.mapping.UpdateLayer(df, nuristanGeol, afgGeol)

This doesn't return anything or update the layers with new symbology. I also tried refreshing the view and TOC. 

What am I doing wrong here? 

Thanks!

Kevin_C

The issue was me trying to use arcpy.mapping.Layer() to define the nuristanGeol feature class which is the layer to be updated. I should've used arcpy.mapping.ListLayers(mxd) to point a variable at nuristanGeol. And then call this variable within UpdateLayer().