You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: lib.rs
    path of file: ./repos/bevy/crates/bevy_animation/src
    
    the code of the file until where you have to start completion: //! Animation for the game engine Bevy

mod animatable;
mod graph;
mod transition;
mod util;

use std::cell::RefCell;
use std::collections::BTreeMap;
use std::hash::{Hash, Hasher};
use std::iter;
use std::ops::{Add, Mul};

    
    fn find_current_keyframe_returns_none_on_finished_animation() {
        let curve = test_variable_curve();
        let max_time = *curve.keyframe_timestamps.last().unwrap();

        assert!(max_time < f32::INFINITY);
        let maybe_keyframe = curve.find_current_keyframe(f32::INFINITY);
        assert!(maybe_keyframe.is_none());

        let maybe_keyframe = curve.find_current_keyframe(max_time);
        assert!(maybe_keyframe.is_none());
    }