code: func (t ValueType) Zero() interface{} {
  	switch t {
  	case TypeInvalid:
  		return nil
  	case TypeBool:
  		return false
  	case TypeInt:
  		return 0
  	case TypeFloat:
  		return 0.0
  	case TypeString:
  		return ""
  	case TypeList:
  		return []interface{}{}
  	case TypeMap:
  		return map[string]interface{}{}
  	case TypeSet:
  		return new(Set)
  	case typeObject:
  		return map[string]interface{}{}
  	default:
  		panic(fmt.Sprintf("unknown type %s", t))
  	}
  }
docs: // Zero returns the zero value for a type.