}
}
impl From<Error> for Box<dyn StdError + 'static> {
    fn from(error: Error) -> Self {
        Box::<dyn StdError + Send + Sync>::from(error)

use anyhow::Error;

use anyhow::{Error, Result};

#[test]
fn test_question_mark() -> Result<(), Box<dyn StdError>> {
    fn f() -> Result<()> {
        Ok(())
    }
    f()?;
    Ok(())
}