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: class.rs
    path of file: ./repos/magnus/src
    
    the code of the file until where you have to start completion: //! Types and functions for working with Ruby classes.
//!
//! See also [`Ruby`](Ruby#core-classes) for more class related methods.

use std::{borrow::Cow, ffi::CStr, fmt, mem::transmute, os::raw::c_int};

#[cfg(ruby_gte_3_1)]
use rb_sys::r
    
    /// fn example(ruby: &Ruby) -> Result<(), Error> {
    ///     let value = ruby.exception_standard_error();
    ///     // safe as we neve give Ruby a chance to free the string.
    ///     let s = unsafe { value.name() }.into_owned();
    ///     assert_eq!(s, "StandardError");
    ///
    ///     Ok(())
    /// }