ndi.fun.timestamp

  TIMESTAMP - return a current time stamp string

  TIMESTAMP_STRING = ndi.fun.timestamp()

  Returns a current time stamp string using the expression:
    TIMESTAMP_STRING = char(datetime('now','TimeZone','UTCLeapSeconds'))

  The string is checked to make sure that the seconds are not
  "60.000", which can occur due to rounding and which can cause a 
  validation error when the data is included in a database.
  In that case, the seconds are set to "59.999".

  Example:
    ts_st = ndi.fun.timestamp()