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: migrations.rs
    path of file: ./repos/kanidm/server/lib/src/server
    
    the code of the file until where you have to start completion: use crate::value::CredentialType;
use std::time::Duration;

use crate::prelude::*;

use kanidm_proto::internal::{
    DomainUpgradeCheckItem as ProtoDomainUpgradeCheckItem,
    DomainUpgradeCheckReport as ProtoDomainUpgradeCheckReport,
    DomainUpgradeCheckStatus as ProtoDomainUpgradeCheckStatus,
};

use 
    
    pub fn migrate_13_to_14(&mut self) -> Result<(), OperationError> {
        admin_warn!("starting 13 to 14 migration.");
        let filter = filter!(f_eq(
            Attribute::Class,
            EntryClass::DynGroup.to_partialvalue()
        ));
        // Delete the incorrectly added "member" attr.
        let modlist = ModifyList::new_purge(Attribute::Member);
        self.internal_modify(&filter, &modlist)
        // Complete
    }