code: def test_days_until(self):
      dates = test_data.test_dates
      diffs = np.arange(0, len(dates))
      _, _, _, o, datetimes = unpack_test_dates(dates)
      date_tensor = dateslib.dates_from_datetimes(datetimes)
  
      target_ordinals = o + diffs
      target_datetimes = [
          datetime.date.fromordinal(o) for o in target_ordinals
      ]
      target_date_tensor = dateslib.dates_from_datetimes(
          target_datetimes
      )
      self.assertAllEqual(
          diffs, date_tensor.days_until(target_date_tensor)
      )
  
imports: import datetime
  import numpy
  import tensorflow.compat.v2
  import tf_quant_finance
  from tf_quant_finance.datetime import test_data
  from tensorflow.python.framework import test_util
label_desc: Use image node_id 16 for calling the DateTensorTest obj's underlying member method code with example usage: obj.test_days_until() without return types