fn is_bytecode_exists(&mut self, bytecode_hash: &H256) -> bool {
        let code_key = get_known_code_key(bytecode_hash);
        self.get_value(&code_key) != H256::zero()
    }
Returns whether a bytecode hash is "known", i.e. whether
it has been published on L1
core/lib/multivm/src/versions/vm_m6/storage.rs