<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def return_real_id(self):
 """ Returns a list of real_id's Parameters Returns ------- A list of real_id values for the dataset (a real_id is the filename minus the suffix and prefix) """

        if self._prepopulated is False:
            raise errors.EmptyDatabase(self.dbpath)
        else:
            return return_real_id_base(self.dbpath, self._set_object)