code: func (f *BasicFilesystem) MkdirAll(path string, perm FileMode) error {
  	path, err := f.rooted(path)
  	if err != nil {
  		return err
  	}
  
  	return f.mkdirAll(path, os.FileMode(perm))
  }
docs: // MkdirAll creates a directory named path, along with any necessary parents,
  // and returns nil, or else returns an error.
  // The permission bits perm are used for all directories that MkdirAll creates.
  // If path is already a directory, MkdirAll does nothing and returns nil.