code: def test_delta_preserve_nanos(self):
      val = Timestamp(1337299200000000123)
      result = val + timedelta(1)
      assert result.nanosecond == val.nanosecond
  
imports: from datetime import datetime, timedelta, timezone
  from dateutil.tz import gettz
  import numpy
  import pytest
  import pytz
  from pandas._libs.tslibs import OutOfBoundsDatetime, OutOfBoundsTimedelta, Timedelta, Timestamp, offsets, to_offset
  import pandas._testing
label_desc: Use image node_id 4 for calling the TestTimestampArithmetic obj's underlying member method code with example usage: obj.test_delta_preserve_nanos() without return types