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: struct.go
    path of file: ./repos/sealer/vendor/github.com/xlab/treeprint
    
    the code of the file until where you have to start completion: package treeprint

import (
	"fmt"
	"reflect"
	"strings"
)

type Struc
    
func checkType(v interface{}) (reflect.Type, *reflect.Value, error) {
	typ := reflect.TypeOf(v)
	val := reflect.ValueOf(v)
	switch typ.Kind() {
	case reflect.Ptr:
		typ = typ.Elem()
		if typ.Kind() != reflect.Struct {
			err := fmt.Errorf("treeprint: %T is not a struct we could work with", v)
			return nil, nil, err
		}
		val = val.Elem()
	case reflect.Struct:
	default:
		err := fmt.Errorf("treeprint: %T is not a struct we could work with", v)
		return nil, nil, err
	}
	return typ, &val, nil
}