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: encryption.rs
    path of file: ./repos/lopdf/src
    
    the code of the file until where you have to start completion: use crate::rc4::Rc4;
use crate::{Document, Object, ObjectId};
use std::fmt;

#[derive(Debug)]
pub enum DecryptionError {
    MissingEncryptDictionary,
    MissingRevision,
    MissingOwn
    
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match self {
            DecryptionError::MissingEncryptDictionary => write!(f, "the /Encrypt dictionary is missing"),
            DecryptionError::MissingRevision => write!(f, "missing encryption revision"),
            DecryptionError::MissingOwnerPassword => write!(f, "missing the owner password (/O)"),
            DecryptionError::MissingPermissions => write!(f, "missing the permissions field (/P)"),
            DecryptionError::InvalidKeyLength => write!(f, "unsupported key length"),
            DecryptionError::InvalidRevision => write!(f, "unsupported revision"),
            DecryptionError::InvalidType => write!(f, "unexpected type; document does not comply with the spec"),
            DecryptionError::MissingFileID => write!(f, "missing the file /ID elements"),
            DecryptionError::NotDecryptable => write!(f, "the object is not capable of being decrypted"),
            DecryptionError::IncorrectPassword => write!(f, "the supplied password is incorrect"),
            DecryptionError::UnsupportedEncryption => {
                write!(f, "the document uses an encryption scheme that is not supported")
            }
        }
    }