use std::sync::{Mutex, MutexGuard};

trait Lock<'a, GUARD: 'a> {
    fn lock(&'a self) -> GUARD;
}

impl<'a, T> Lock<'a, MutexGuard<'a, T>> for Mutex<T> {
    fn lock(&'a self) -> MutexGuard<'a, T> {
        self.lock().unwrap()
    }
}