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: tags_templatetag.go
    path of file: ./repos/faygo/vendor/github.com/flosch/pongo2
    
    the code of the file until where you have to start completion: package pongo2

type tagTemplateTagNode struct {
	content string
}

var templateTagMapping = map[string]string{
	"openblock":     "{%",
	"closeblock":    "%}",
	"openvariable":  "{{",
	"closevariable": "}}",
	"openbrace":     "{",
	"closebrace":    "}",
	"opencomment":   "{#",
	"closecomment":  "#}",
}

func (node *tagTemplateTagNode) Execute(ctx *ExecutionContext, writer TemplateWriter) *Error {
	writer.WriteString(node.conten
    
func tagTemplateTagParser(doc *Parser, start *Token, arguments *Parser) (INodeTag, *Error) {
	ttNode := &tagTemplateTagNode{}

	if argToken := arguments.MatchType(TokenIdentifier); argToken != nil {
		output, found := templateTagMapping[argToken.Val]
		if !found {
			return nil, arguments.Error("Argument not found", argToken)
		}
		ttNode.content = output
	} else {
		return nil, arguments.Error("Identifier expected.", nil)
	}

	if arguments.Remaining() > 0 {
		return nil, arguments.Error("Malformed templatetag-tag argument.", nil)
	}

	return ttNode, nil
}