docs: def get_multiplicons_at_level(self, level, redundant=False):
          """ Return a list of IDs of multiplicons at the requested level
          """
          sql = '''SELECT id FROM multiplicons
                     WHERE level=:level'''
          cur = self._dbconn.cursor()
          cur.execute(sql, {'level': str(level)})
          result = [int(r[0]) for r in cur.fetchall()]
          cur.close()
          if redundant:
              return result
          else:
              return [r for r in result if not self.is_redundant_multiplicon(r)]