code: def EndEdit(self, row, col, grid, oldVal=None):
          
  
          # Mirror our changes onto the main_window's code bar
          self._tc.Unbind(wx.EVT_KEY_UP)
  
          self.ApplyEdit(row, col, grid)
  
          del self._col
          del self._row
          del self._grid
docs: End editing the cell.  This function must check if the current
          value of the editing control is valid and different from the
          original value (available as oldval in its string form.)  If
          it has not changed then simply return None, otherwise return
          the value in its string form.
          *Must Override*