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: distant.rs
    path of file: ./repos/rs_pbrt/src/lights
    
    the code of the file until where you have to start completion: // std
use std::cell::Cell;
use std::f32::consts::PI;
use std::sync::RwLock;
// pbrt
use crate::core::geometry::vec3_coordinate_system;
use crate::core::geometry::{Bounds3f, Normal3f, Poin
    
    pub fn preprocess(&self, scene: &Scene) {
        let mut world_center_ref = self.world_center.write().unwrap();
        let mut world_radius_ref = self.world_radius.write().unwrap();
        Bounds3f::bounding_sphere(
            scene.world_bound(),
            &mut world_center_ref,
            &mut world_radius_ref,
        );
    }