code: def rename_columns(self, rename_dict):
          
          if not all([x in self._columns for x in rename_dict.keys()]):
              raise ValueError('all dictionary keys must be in current columns')
          for current in rename_dict.keys():
              self._columns[self._columns.index(current)] = rename_dict[current]
docs: Renames the columns
  
          :param rename_dict: dict where the keys are the current column names and the values are the new names
          :return: nothing