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: Mime.go
    path of file: ./repos/grule-rule-engine/editor/mime
    
    the code of the file until where you have to start completion: /*-----------------------------------------------------------------------------------
  --  HttpTarget                                                                   
    
func GetMimeForFileName(filename string) (string, error) {
	reg := regexp.MustCompile(`[a-zA-Z0-9]+$`)
	if reg.MatchString(filename) {
		ext := reg.FindString(filename)

		return GetMimeForExtension(ext)
	}

	return "", fmt.Errorf("can not find extension of file : %s", filename)
}