code: func (c *ChtIndexerBackend) Reset(ctx context.Context, section uint64, lastSectionHead common.Hash) error {
  	var root common.Hash
  	if section > 0 {
  		root = GetChtRoot(c.diskdb, section-1, lastSectionHead)
  	}
  	var err error
  	c.trie, err = trie.New(root, c.triedb)
  
  	if err != nil && c.odr != nil {
  		err = c.fetchMissingNodes(ctx, section, root)
  		if err == nil {
  			c.trie, err = trie.New(root, c.triedb)
  		}
  	}
  
  	c.section = section
  	return err
  }
docs: // Reset implements core.ChainIndexerBackend