function getStartTimeAsDateObject_(dateTimeStr) {
  if (!dateTimeStr || !dateTimeStr.match(DATE_TIME_PATTERN)) {
    return null;
  }

  const parts = dateTimeStr.split(' ');
  const [month, day, year] = parts[0].split('/').map(Number);
  const [hour, minute] = parts[1].split(':').map(Number);
  
  
  Session.getScriptTimeZone()
  
  return new Date(year, month - 1, day, hour, minute)
}
Casts date and time from string to Date object.
@return {date}