anchor.diff:        , {store,  lists:sort(maps:to_list(state(C)))}
         ]).
   
  --spec deserialize_from_poi(aec_keys:pubkey(), serialized()) -> contract().
  +-spec deserialize_from_poi(id(), serialized()) -> contract().
   deserialize_from_poi(Pubkey, Bin) ->
       [ {owner, OwnerId}
       , {vm_version, VmVersion}
  
positive.code:       , {deposit, deposit(C)}
        ]).
  
  -spec deserialize(aec_keys:pubkey(), serialized()) -> contract().
  deserialize(Pubkey, Bin) ->
      [ {owner, OwnerId}
      , {vm_version, VmVersion}
  
negative.code: %%%===================================================================
  %%% Setters
  
  -spec set_pubkey(id(), contract()) -> contract().
  set_pubkey(X, C) ->
      C#contract{id = aec_id:create(contract, assert_field(pubkey, X))}.
  
  