service : { account_id : () -> (text) query; withdraw : (blob) -> (); post : (record { price : nat64; canister_id : principal}) -> (); unpost : (nat64) -> (); buy : (nat64) -> (); catalog : () -> (vec record { lot : nat64; canister_id : principal; price : nat64; seller : principal; controllers : vec principal; }) query; }