code: def sort(self, column_name=None, reverse=False):
          
          if not column_name and self.options.has_key('sorted_by'):
              column_name = self.options['sorted_by'].keys()[0]
          if column_name not in self.default_columns:
              raise ValueError("%s isn't a column in this table" % column_name)
          index = self.default_columns.index(column_name)
          self.table.sort(key = lambda row: row[index], reverse=reverse)
          self.options['sorted_by'] = {column_name: {'reverse': reverse}}
docs: Sort rows in this table, preserving a record of how that
          sorting is done in TableFu.options['sorted_by']