typed.go
func (t Typed) Map(key string) map[string]interface{} {
	return t.MapOr(key, nil)
}
func (t Typed) Map(key string) map[string]interface{} {
	return t.MapOr(key, nil)
}
// Returns a map[string]interface{} at the key
// or a nil map if the key doesn't exist or if the key isn't
// a map[string]interface