code: def testIncremental(self):
      size = 20
      ds1 = dataseries.SequenceDataSeries()
      ds2 = dataseries.SequenceDataSeries()
      ads1, ads2 = aligned.datetime_aligned(ds1, ds2)
  
      now = datetime.datetime.now()
      for i in xrange(size):
          ds1.appendWithDateTime(now + datetime.timedelta(seconds=i), i)
          ds2.appendWithDateTime(now + datetime.timedelta(seconds=i), i)
          self.assertEqual(len(ads1), len(ads2))
          self.assertEqual(ads1[:], ads2[:])
          self.assertEqual(
              ads1.getDateTimes()[:], ads2.getDateTimes()[:]
          )
  
imports: import datetime
  from six.moves import xrange
  from .None import common
  from pyalgotrade import dataseries
  from pyalgotrade.dataseries import bards
  from pyalgotrade.dataseries import aligned
  from pyalgotrade import bar
label_desc: Use image node_id 4 for calling the TestDateAlignedDataSeries obj's underlying member method code with example usage: obj.testIncremental() without return types