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: upstream_categories.rs
    path of file: ./repos/ruff/crates/ruff_linter/src
    
    the code of the file until where you have to start completion: //! This module should probably not exist in this shape or form.
use crate::codes::Rule;
use crate::registry::Linter;

#[derive(Hash, Eq, PartialEq, Copy, Clone, Debug)]
pub struct UpstreamCategoryAndPrefix {
    pub category: &'static str,
    pub prefix: &'static str,
}

const PLC: UpstreamCategoryAndPrefix = UpstreamCategoryAndPrefix {
    category: "Convention",
    prefix: "PLC",
};

const PLE: UpstreamCategoryAndPrefix = UpstreamC
    
    pub fn upstream_category(&self, linter: &Linter) -> Option<UpstreamCategoryAndPrefix> {
        let code = linter.code_for_rule(*self).unwrap();
        match linter {
            Linter::Pycodestyle => {
                if code.starts_with('E') {
                    Some(E)
                } else if code.starts_with('W') {
                    Some(W)
                } else {
                    None
                }
            }
            Linter::Pylint => {
                if code.starts_with("PLC") {
                    Some(PLC)
                } else if code.starts_with("PLE") {
                    Some(PLE)
                } else if code.starts_with("PLR") {
                    Some(PLR)
                } else if code.starts_with("PLW") {
                    Some(PLW)
                } else {
                    None
                }
            }
            _ => None,
        }
    }