code: def sort_ascending(self, key):
          
  
          row, col, tab = key
  
          scells = self.grid.code_array[:, col, tab]
  
          def sorter(i):
              sorted_ele = scells[i]
              return sorted_ele is None, sorted_ele
  
          sorted_row_idxs = sorted(xrange(len(scells)), key=sorter)
  
          self.replace_cells(key, sorted_row_idxs)
  
          self.grid.ForceRefresh()
docs: Sorts selection (or grid if none) corresponding to column of key