code: func AddFile(file string, opts ...FileOption) error {
  	o := &FileOptions{}
  	for _, f := range opts {
  		f(o)
  	}
  	if err := fs.AddFile(file, filesource.DefaultFilePriority, o.Handler); err != nil {
  		return err
  	}
  	return factory.Refresh(fs.GetSourceName())
  }
docs: // AddFile is for to add the configuration files into the configfactory at run time