You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: schema.go
    path of file: ./repos/moby/vendor/github.com/hashicorp/go-memdb
    
    the code of the file until where you have to start completion: package memdb

import "fmt"

// DBSchema is the schema to use for the full database with a MemDB instance
    
func (s *IndexSchema) Validate() error {
	if s.Name == "" {
		return fmt.Errorf("missing index name")
	}
	if s.Indexer == nil {
		return fmt.Errorf("missing index function for '%s'", s.Name)
	}
	switch s.Indexer.(type) {
	case SingleIndexer:
	case MultiIndexer:
	default:
		return fmt.Errorf("indexer for '%s' must be a SingleIndexer or MultiIndexer", s.Name)
	}
	return nil
}