pub fn sighash(name: &str) -> [u8; 8] {
let namespace = "global";
let preimage = format!("{}:{}", namespace, name);
let mut sighash = [0u8; 8];
sighash.copy_from_slice(
&anchor_lang::solana_program::hash::hash(preimage.as_bytes()).to_bytes()[..8],
);
sighash
}