450         return rqlst

   450         return rqlst

   451 

   451 

   452     @cached

   452     @cached

   453     def column_types(self, col):

   453     def column_types(self, col):

   454         """return the list of different types in the column with the given col

   454         """return the list of different types in the column with the given col

   456 

   455 

   457         :type col: int

   456         :type col: int

   458         :param col: the index of the desired column

   457         :param col: the index of the desired column

   459 

   458 

   460         :rtype: list

   459         :rtype: list