Unable to replace data source from a layer in an ArcGIS MapDocument

Question

I'm trying to write a code for automating changing the source for some layers of a mxd document. I have three layers that should point to the same shapefile, they are only displayed with different symbology in the map. So, here is a version of what I tried:

#in this example, the shapefile I want is "C:\\Users\\USER_NAME\\folder\\new_shape.shp"
#this new shapefile IS NOT in the same directory as the previous one
#also, I tried first changing only one layer

import arcpy
mxd = arcpy.mapping.MapDocument('current')
principal = arcpy.mapping.ListDataFrames(mxd)[0]

lyr1 = arcpy.mapping.ListLayers('current', '', principal)[5]
lyr2 = arcpy.mapping.ListLayers('current', '', principal)[6]
lyr3 = arcpy.mapping.ListLayers('current', '', principal)[7]

lyr1.replaceDataSource("C:\\Users\\USER_NAME\\folder", "SHAPEFILE_WORKSPACE", 'new_shape')

From all the examples I found, this should do the trick. However, when I open the MXD, the layer's datasource is the same as before. This happens for any of the three layers.

I really couldn't figure out what is wrong in this code.

I'm using ArcGIS 10.5 and Python 2.7

Answer 1

Someone from outside StackOverflow was able to help me, so I will share the solution, which was quite simple.

Adding '\\' to the end on my folder path made everything work fine for me!

I really have no idea why, since I haven't seen this in any of the examples I could find online, though.

But adding the .shp suffix to the shapefile name returns a ValueError, so ajusting only the path is the answer.