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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def dump_np_vars(self, store_format='csv', delimiter=','):
 """ Dump the TDS simulation data to files by calling subroutines `write_lst` and `write_np_dat`. Parameters store_format : str dump format in `('csv', 'txt', 'hdf5')` delimiter : str delimiter for the `csv` and `txt` format Returns ------- bool: success flag """


        ret = False

        if self.system.files.no_output is True:
            logger.debug('no_output is True, thus no TDS dump saved ')
            return True

        if self.write_lst() and self.write_np_dat(store_format=store_format, delimiter=delimiter):
            ret = True

        return ret