code: def is_redundant_multiplicon(self, value):
          
          if not hasattr(self, '_redundant_multiplicon_cache'):
              sql = '''SELECT id FROM multiplicons WHERE is_redundant="-1"'''
              cur = self._dbconn.cursor()
              cur.execute(sql, {'id': str(value)})
              result = [int(r[0]) for r in cur.fetchall()]
              self._redundant_multiplicon_cache = set(result)
          if value in self._redundant_multiplicon_cache:
              return True
          else:
              return False
docs: Returns True if the passed multiplicon ID is redundant, False
              otherwise.
  
              - value, (int) multiplicon ID