def ext_to_delimiter(extension: str) -> str:
    """Convert file extension to delimiter

    :param extension: file extension ("txt", "csv", "tsv")
    :return: the delimiter (",", " ", "\t")
    """
    if extension == "csv":
        delimiter = ","
    elif extension == "tsv":
        delimiter = "\t"
    elif extension == "txt":
        delimiter = " "
    else:
        raise ValueError("File extension not recognized!"
                         " (Use txt, tsv, or csv)")

    return delimiter