type ParachainBlockImport = TParachainBlockImport<Block, Arc<ParachainClient>, ParachainBackend>;
let relay_slot = sp_consensus_aura::inherents::InherentDataProvider::from_timestamp_and_slot_duration(
additional_keys.append(&mut vec![(para_head_key, para_head_data), (relay_slot_key, Slot::from(relay_slot).encode())]);