module example::example {
    use pyth::pyth;
    use pyth::price::Price;
    use pyth::price_identifier;
    use aptos_framework::coin;
    
    /// Updates the Pyth price feeds using the given pyth_update_data, and then returns 
    /// the BTC/USD price.
    public fun get_btc_usd_price(user: &signer, pyth_update_data: vector<vector<u8>>): Price {

        // First update the Pyth price feeds
        let coins = coin::withdraw(user, pyth::get_update_fee());
        pyth::update_price_feeds(pyth_update_data, coins);

        // Price Feed Identifier of BTC/USD in Testnet
        let btc_price_identifier = x"f9c0172ba10dfa4d19088d94f5bf61d3b54d5bd7483a322a982e1373ee8ea31b";

        // Now we can use the prices which we have just updated
        let btc_usd_price_id = price_identifier::from_byte_vec(btc_price_identifier);
        pyth::get_price(btc_usd_price_id)

    }
}