def _build_return_params_message(types, values):
    """
    Build the return message with the parameters output.

    :param types: List of the parameter's types
    :param values: List of the parameter's values
    :return: Message as string
    """

    assert len(types) == len(values), 'Inconsistent state: return type-value length mismatch for return message.'

    pairs = list(zip(types, values))
    num_params = len(pairs)
    params = ''
    for pair in pairs:
        params = params + str(pair[0]) + ' ' + str(pair[1]) + ' '
    message = str(num_params) + ' ' + params
    return message