def gen_oo_textgrid_str(begin_t, end_t, duration, transcript, speaker_name)->str:
    """Creates a TextGrid file in oo-format with only one entry as the transcript
    with begins and ends at begin_t and end_t, respectively.

    Args:
        begin_t (float): beginning time
        end_t (float): end time
        transcript (str): uppercase transcript
    Returns:
        (str): string format of textgrid
    """
    oo_file = ""
    oo_file += "File type = \"ooTextFile\"\n"
    oo_file += "Object class = \"TextGrid\"\n\n"
    oo_file += "xmin = 0.0\n"
    oo_file += f"xmax = {duration}\n"
    oo_file += "tiers? <exists>\n"
    oo_file += "size = 1\n"
    oo_file += "item []:\n"
    
    oo_file += "%4s%s [%s]:\n" % ("", "item", 1)
    
    oo_file += "%8s%s = \"%s\"\n" % ("", "class", "IntervalTier")
    oo_file += "%8s%s = \"%s\"\n" % ("", "name", speaker_name)
    oo_file += "%8s%s = %s\n" % ("", "xmin", begin_t)
    oo_file += "%8s%s = %s\n" % ("", "xmax", end_t)
    oo_file += "%8s%s: %s\n" % ("", "interals", "size = 1")
    
    oo_file += "%12s%s\n" % ("", "intervals [1]:")
    
    oo_file += "%16s%s = %s\n" % ("", "xmin", begin_t)
    oo_file += "%16s%s = %s\n" % ("", "xmax", end_t)
    oo_file += "%16s%s = \"%s\"\n" % ("", "text", transcript)

    return oo_file