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: ast_values.go
    path of file: ./repos/rill/runtime/pkg/duckdbsql
    
    the code of the file until where you have to start completion: package duckdbsql

import "strings"

// TODO: figure out a way to cast map[string]interface{} returned by json unmarshal to map[astNodeKey]interface{} and replace string in key to astNodeKey
type astNode map[string]interface{}

const (
	astKeyError            string = "error"
	astKeyErrorMessage     string = "error_message"
	astKeyStatements       string = "statements"
	astKeyNode             string = "node"
	astKeyType             string = "type"
	astKeyKey              string = "key"
	astKeyFromTable        string = "from_table"
	astKeySelectColumnList string = 
    
func getListOfValues[E interface{}](a astNode) []E {
	arr := make([]E, 0)
	switch toString(a, astKeyType) {
	case "VALUE_CONSTANT":
		if vt, ok := a[astKeyValue].(map[string]interface{})[astKeyValue].(E); ok {
			arr = append(arr, vt)
		}

	case "FUNCTION":
		if toString(a, astKeyFunctionName) == "list_value" {
			for _, child := range toNodeArray(a, astKeyChildren) {
				if toString(child, astKeyType) != "VALUE_CONSTANT" {
					continue
				}
				if vt, ok := child[astKeyValue].(map[string]interface{})[astKeyValue].(E); ok {
					arr = append(arr, vt)
				}
			}
		}
	}
	return arr
}