to be able to use " / ", it need to be an instance of Path. So simply wrap your path like so:
path = Path("/content/drive/My Drive/Umes")
this will make all the subsequent variables of type Path if you use the “/” operator. So update path_img and path_lbl to:
path_img = path/'Images'
path_lbl = path/'labels
The main issue was path_lbl not being an instance of Path.