new_contents: from datetime import datetime
  import numpy as np
  from numpy.lib.recfunctions import drop_fields, append_fields
  
  class NLDNdataFile(object):
      
      stroke_DC3 = {'columns':[ ('date','S10'), ('time','S20'), 
                                ('lat','f4'), ('lon','f4'), 
                                ('peakCurrent','f4'), ('ellipse','f4'),
                                ], 
                    'date_dtype':[('year','i2'),('month','i1'),('day','i1')],
                    'time_dtype':[('hour','i1'),('minute','i1'),('second','float64')]
                   }
      
      def __init__(self, filename, date_sep='-', time_sep=':', format='stroke_DC3'):
          self.format=format
          
          dtype_specs = getattr(self, format)
          
          
          nldn_initial = np.genfromtxt(filename, dtype=dtype_specs['columns'])
          date_part = np.genfromtxt(nldn_initial['date'],
                          delimiter=date_sep, dtype=dtype_specs['date_dtype'])
          time_part = np.genfromtxt(nldn_initial['time'],
                          delimiter=time_sep, dtype=dtype_specs['time_dtype'])
          dates = [datetime(a['year'], a['month'], a['day'], b['hour'], b['minute']) 
                      for a, b in zip(date_part, time_part)]
          min_date = min(dates)
          t = np.fromiter( ((d-min_date).total_seconds() for d in dates), dtype='float64')
          t += time_part['second']
          
          self.basedate = min_date
          data = drop_fields(nldn_initial, ('date', 'time'))
          data = append_fields(data, 'time', t)
          
          self.data = data
          
subject: Add NLDN file reader