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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 check_work_done(self, grp):
 """ Check for the existence of alignment and result files. """

        id_ = self.get_id(grp)
        concat_file = os.path.join(self.cache_dir, '{}.phy'.format(id_))
        result_file = os.path.join(self.cache_dir, '{}.{}.json'.format(id_, self.task_interface.name))
        return os.path.exists(concat_file), os.path.exists(result_file)