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: mod.rs
    path of file: ./repos/dfdx/dfdx-core/src/tensor/cpu
    
    the code of the file until where you have to start completion: mod allocate;
mod device;
mod index;
mod iterate;

pub(crate) use index
    
    fn test_empty_cache() {
        let dev: Cpu = Default::default();
        dev.enable_cache();
        let tensor: Tensor<Rank2<2, 3>, f32, _> = dev.zeros();
        drop(tensor); // insert allocation into cache
        assert_eq!(dev.cache.len(), 1);
        dev.empty_cache();
        assert_eq!(dev.cache.len(), 0);
    }