torchsparse running issue

Hi, tanks for your awesome work.
I follow your installation guid using 
    - pytorch 1.13.1
    - torchsparse 1.4
    - cuda 11.7

but when i running the infernce code , i get error

``` bash
AttributeError: module 'torchsparse.backend' has no attribute 'build_kernel_map_subm_hashmap
```

do you have another setting? 
my machine is 4090 cuda with driver 12.4