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: make_testdata.rs
    path of file: ./repos/icu4x/provider/datagen/src/tests
    
    the code of the file until where you have to start completion: // This file is part of ICU4X. For terms of use, please see the file
// called LICENSE at the top level of the ICU4X source tree
// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).

use crate::prelude::*;
use crlify
    
    fn close(&mut self) -> Result<(), DataError> {
        for ((key, locale), (size, hash)) in self.size_hash.get_mut().expect("poison") {
            writeln!(&mut self.fingerprints, "{key}, {locale}, {size}B, {hash:x}")?;
        }

        assert_eq!(
            self.rountrip_errors.get_mut().expect("poison"),
            &mut BTreeSet::default()
        );

        let violations = self
            .zero_copy_violations
            .get_mut()
            .expect("poison")
            .iter()
            .copied()
            .collect::<Vec<_>>();

        let transient_violations = self
            .zero_copy_transient_violations
            .get_mut()
            .expect("poison")
            .iter()
            .copied()
            .collect::<Vec<_>>();

        assert!(transient_violations == EXPECTED_TRANSIENT_VIOLATIONS && violations == EXPECTED_VIOLATIONS,
            "Expected violations list does not match found violations!\n\
            If the new list is smaller, please update EXPECTED_VIOLATIONS in make-testdata.rs\n\
            If it is bigger and that was unexpected, please make sure the key remains zero-copy, or ask ICU4X team members if it is okay\
            to temporarily allow for this key to be allowlisted.\n\
            Expected:\n{EXPECTED_VIOLATIONS:?}\nFound:\n{violations:?}\nExpected (transient):\n{EXPECTED_TRANSIENT_VIOLATIONS:?}\nFound (transient):\n{transient_violations:?}"
        );

        Ok(())
    }