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: tx_change_validator_metadata.rs
    path of file: ./repos/namada/wasm/wasm_source/src
    
    the code of the file until where you have to start completion: //! A tx for a validator to change various metadata, including its commission
//! rate.

use namada_tx_prelude::transaction::pos::MetaDataChange;
use namada_tx_prelude::*;

// TODO: need to benchmark 
    
fn apply_tx(ctx: &mut Ctx, tx_data: Tx) -> TxResult {
    let signed = tx_data;
    let data = signed.data().ok_or_err_msg("Missing data")?;
    let MetaDataChange {
        validator,
        email,
        description,
        website,
        discord_handle,
        avatar,
        commission_rate,
    } = transaction::pos::MetaDataChange::try_from_slice(&data[..])
        .wrap_err("failed to decode Dec value")?;
    ctx.change_validator_metadata(
        &validator,
        email,
        description,
        website,
        discord_handle,
        avatar,
        commission_rate,
    )
}