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: error.rs
    path of file: ./repos/skytable/harness/src
    
    the code of the file until where you have to start completion: /*
 * Created on Thu Mar 17 2022
 *
 * This file is a part of Skytable
 * Skytable (
    
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            HarnessError::BadArguments(arg) => write!(f, "Bad arguments: `{}`", arg),
            HarnessError::UnknownCommand(cmd) => write!(f, "Unknown command: `{}`", cmd),
            HarnessError::ChildError(desc, code) => match code {
                Some(code) => write!(f, "The child (`{desc}`) exited with code {code}"),
                None => write!(f, "The child (`{desc}`) exited with a non-zero code"),
            },
            HarnessError::Other(other) => write!(f, "{other}"),
        }
    }