def _make_signal_unique(signal_name: str, db: dict) -> str:
    """
    Preserve duplicated signal in WaveDrom format by adding
    extra space that will be removed later on.
    Add as many spaces it is required to make the identifier unique.
    """
    new_name = signal_name
    while new_name in db:
        new_name += " "
    return new_name