func IsBlank(id ast.Expr) bool {
	ident, _ := id.(*ast.Ident)
	return ident != nil && ident.Name == "_"
}
func IsBlank(id ast.Expr) bool {
	ident, _ := id.(*ast.Ident)
	return ident != nil && ident.Name == "_"
}
// isBlank returns whether id is the blank identifier "_".
// If id == nil, the answer is false.