anchor.diff:            oracle_ttl    => {delta, TTL},
             ttl           => 0, %% Not used.
             fee           => 0},
  +    {ok, Tx} = aeo_register_tx:new(Spec),
   
       %% TODO: To register an oracle for another account than the contract
       %%       we need a safe way to sign the register call.
  
positive.code:         {ok, aevm_chain_api:call_result(), chain_state()} | {error, term()}.
  call_contract(Target, Gas, Value, CallData, CallStack,
                State = #state{ trees   = Trees,
                                height  = Height,
                                account = ContractKey
                              }) ->
      ConsensusVersion = aec_hard_forks:protocol_effective_at_height(Height),
      CT = aec_trees:contracts(Trees),
      case aect_state_tree:lookup_contract(Target, CT) of
          {value, Contract} ->
  
negative.code: 	end,
      aect_state_tree:enter_contract(NewContract, ContractsTree).
  
  apply_transaction(Tx, #state{ trees = Trees, height = Height } = State) ->
      ConsensusVersion = aec_hard_forks:protocol_effective_at_height(Height),
      case aetx:check_from_contract(Tx, Trees, Height, ConsensusVersion) of
          {ok, Trees1} ->
              {ok, Trees2} =
                  aetx:process_from_contract(Tx, Trees1, Height, ConsensusVersion),
              State1 = State#state{ trees = Trees2 },
              {ok, State1};
          {error, _} = E -> E
      end.
  
  next_nonce(State = #state{ account = ContractKey }) ->
      next_nonce(ContractKey, State).
  
  next_nonce(Addr, #state{ trees = Trees }) ->
      AT = aec_trees:accounts(Trees),
      {value, Account} = aec_accounts_trees:lookup(Addr, AT),
      aec_accounts:nonce(Account) + 1.
  
  