use crate::{Error, Result};
pub fn apply<T: Required>(v: &T, _: ()) -> Result {
if !v.is_set() {
return Err(Error::new("not set"));
}
Ok(())
}
pub trait Required {
fn is_set(&self) -> bool;
}
impl<T> Required for Option<T> {
fn is_set(&self) -> bool {
self.is_some()
}
}