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: errors.rs
    path of file: ./repos/enigma-core/enigma-core/app/src/common_u
    
    the code of the file until where you have to start completion: #![allow(dead_code)]
use sgx_types::*;
use std::fmt;
use failure::Error;

// error while requesting to produce a quote (registration)
#[derive(Fail, Debug)]
#[fail(display = "Error while producing a quote sgx_status = {}. info = ({})", status, message)]
pub struct ProduceQuoteErr {
    pub status: sgx_status_t,
    pub message: String,
}

#[derive(Fail, Debug)]
#[fail(display = "Error while decoding the quote = ({})", message)]
pub struct QuoteErr {
    
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        let printable: String = match &*self {
            DBErrKind::KeyExists(k) => format!("the key already exists for the following address: {:?}", &k),
            DBErrKind::CreateError => "Failed to create the key".into(),
            DBErrKind::FetchError => "Failed to fetch the data".into(),
            DBErrKind::MissingKey(k) => format!("The following Key doesn't exist: {}", &k),
            DBErrKind::UpdateError => "Failed to update the key".into(),
            DBErrKind::MissingKeys => "No keys exist the DB".into(),
        };
        write!(f, "{}", printable)
    }