code: def setup_columns(self):
          
          tv = self.view['tv_categories']
  
          # sets the model
          tv.set_model(self.model)
          
          # creates the columns
          cell = gtk.CellRendererText()
          tvcol = gtk.TreeViewColumn('Name', cell)
  
          def cell_data_func(col, cell, mod, it):
              if mod[it][0]: cell.set_property('text', mod[it][0].name)
              return
          tvcol.set_cell_data_func(cell, cell_data_func)
          
          tv.append_column(tvcol)                
          return
docs: Creates the treeview stuff