func (w *Walker) ImportFrom(fromPath, fromDir string, mode types.ImportMode) (*types.Package, error) {
	pkg, err := w.importFrom(fromPath, fromDir, mode)
	if err != nil {
		return nil, err
	}
	return pkg.Package, nil
}

func (w *Walker) import_(name string) (*apiPackage, error) {
	return w.importFrom(name, "", 0)
}

func (w *Walker) importFrom(fromPath, fromDir string, mode types.ImportMode) (*apiPackage, error) {