#[derive(Clone, Debug, thiserror::Error)]
pub enum Pop {
#[error("The pile is empty")]
Empty,
}
#[derive(Clone, Debug, thiserror::Error)]
pub enum Insert {
#[error("The index ({0}/{1}) is invalid")]
Index(usize, usize),
}
#[derive(Clone, Debug, thiserror::Error)]
pub enum Remove {
#[error("The index ({0}/{1}) is invalid")]
Index(usize, usize),
}