"""

    If `message.current` is empty then it creates a smart contract

    else it executes a call from the `message.caller` to the `message.target`.

    Parameters

    ----------

    message :

        Transaction specific items.

    env :

        External items required for EVM execution.

    Returns

    -------

    output : `MessageCallOutput`

        Output of the message call

    """

    if message.target == Bytes0(b""):

        is_collision = account_has_code_or_nonce(

            env.state, message.current_target

        ) or account_has_storage(env.state, message.current_target)

        if is_collision:

            return MessageCallOutput(

                Uint(0), U256(0), tuple(), set(), AddressCollision()

            )

        else:

            evm = process_create_message(message, env)

    else:

        evm = process_message(message, env)

    if evm.error:

        logs: Tuple[Log, ...] = ()

        accounts_to_delete = set()

        refund_counter = U256(0)

    else:

        logs = evm.logs

        accounts_to_delete = evm.accounts_to_delete

        refund_counter = U256(evm.refund_counter)

    tx_end = TransactionEnd(

        int(message.gas) - int(evm.gas_left), evm.output, evm.error

    )

    evm_trace(evm, tx_end)

    return MessageCallOutput(

        gas_left=evm.gas_left,

        refund_counter=refund_counter,

        logs=logs,

        accounts_to_delete=accounts_to_delete,

        error=evm.error,

    )

    """

    Executes a call to create a smart contract.

    Parameters

    ----------

    message :

        Transaction specific items.

    env :

        External items required for EVM execution.

    Returns

    -------

    evm: :py:class:`~ethereum.frontier.vm.Evm`

        Items containing execution specific objects.

    """

    # take snapshot of state before processing the message

    begin_transaction(env.state)

    # If the address where the account is being created has storage, it is

    # destroyed. This can only happen in the following highly unlikely

    # circumstances:

    # * The address created by two `CREATE` calls collide.

    # * The first `CREATE` left empty code.

    destroy_storage(env.state, message.current_target)

    evm = process_message(message, env)

    if not evm.error:

        contract_code = evm.output

        contract_code_gas = Uint(len(contract_code)) * GAS_CODE_DEPOSIT

        try:

            charge_gas(evm, contract_code_gas)

        except ExceptionalHalt:

            evm.output = b""

        else:

            set_code(env.state, message.current_target, contract_code)

        commit_transaction(env.state)

    else:

        rollback_transaction(env.state)

    return evm

    """

    Executes a call to create a smart contract.

    Parameters

    ----------

    message :

        Transaction specific items.

    env :

        External items required for EVM execution.

    Returns

    -------

    evm: :py:class:`~ethereum.frontier.vm.Evm`

        Items containing execution specific objects

    """

    if message.depth > STACK_DEPTH_LIMIT:

        raise StackDepthLimitError("Stack depth limit reached")

    # take snapshot of state before processing the message

    begin_transaction(env.state)

    touch_account(env.state, message.current_target)

    if message.value != 0:

        move_ether(

            env.state, message.caller, message.current_target, message.value

        )

    evm = execute_code(message, env)

    if evm.error:

        # revert state to the last saved checkpoint

        # since the message call resulted in an error

        rollback_transaction(env.state)

    else:

        commit_transaction(env.state)

    return evm

    """

    Executes bytecode present in the `message`.

    Parameters

    ----------

    message :

        Transaction specific items.

    env :

        External items required for EVM execution.

    Returns

    -------

    evm: `ethereum.vm.EVM`

        Items containing execution specific objects

    """

    code = message.code

    valid_jump_destinations = get_valid_jump_destinations(code)

    evm = Evm(

        pc=Uint(0),

        stack=[],

        memory=bytearray(),

        code=code,

        gas_left=message.gas,

        env=env,

        valid_jump_destinations=valid_jump_destinations,

        logs=(),

        refund_counter=0,

        running=True,

        message=message,

        output=b"",

        accounts_to_delete=set(),

        error=None,

    )

    try:

        if evm.message.code_address in PRE_COMPILED_CONTRACTS:

            evm_trace(evm, PrecompileStart(evm.message.code_address))

            PRE_COMPILED_CONTRACTS[evm.message.code_address](evm)

            evm_trace(evm, PrecompileEnd())

            return evm

        while evm.running and evm.pc < ulen(evm.code):

            try:

                op = Ops(evm.code[evm.pc])

            except ValueError:

                raise InvalidOpcode(evm.code[evm.pc])

            evm_trace(evm, OpStart(op))

            op_implementation[op](evm)

            evm_trace(evm, OpEnd())

        evm_trace(evm, EvmStop(Ops.STOP))

    except ExceptionalHalt as error:

        evm_trace(evm, OpException(error))

        evm.gas_left = Uint(0)

        evm.error = error

    return evm