 
   from astroplpython.data.TimeMeasurement import x_t
   from astroplpython.function.signal.LSPeriodogram import LSPeriodogram
+  from astroplpython.exception.ListException import EmptyListException
 
   # debugging?
   import logging

  pgram = []
  try:
      pgram = LSPeriodogram.calculate(x_t.dbStrToArray(data), f_low, f_high, f_bins)
  except EmptyListException as e:
      log.warn ("calc_lsp was passed an empty list, ignoring");

  return pgram


  from astroplpython.data.PowerFrequencyMeasurement import p_f
  from astroplpython.function.statistic.Maximum import Maximum

  import logging
  import sys
  logging.basicConfig(stream=sys.stderr)
  log = logging.getLogger( "astroplpython.function.statistic")

  p_f_list = []
  # calculate based on passed parameters
  try:
     max = Maximum.calculate(p_f.dbStrToArray(data))
     # postgres requires return of an 'iterable object' 
     p_f_list.append(max)
  except ValueError as ve:
     log.warn ("max_power got ValueError, ignoring");
     p_f_list.append(p_f("-1", "-1"))

  return p_f_list

