code: func (ns *Namespace) FileExists(i interface{}) (bool, error) {
  	path, err := cast.ToStringE(i)
  	if err != nil {
  		return false, err
  	}
  
  	if path == "" {
  		return false, errors.New("fileExists needs a path to a file")
  	}
  
  	status, err := afero.Exists(ns.readFileFs, path)
  	if err != nil {
  		return false, err
  	}
  
  	return status, nil
  }
docs: // FileExists checks whether a file exists under the given path.