code: def test_simple_assign_datetime(self, container: MetadataContainer):
      key = self.gen_key()
      now = datetime.now()
  
      container[key] = now
      container.sync()
  
      # expect truncate to milliseconds and add UTC timezone
      expected_now = now.astimezone(timezone.utc).replace(
          microsecond=int(now.microsecond / 1000) * 1000
      )
      assert container[key].fetch() == expected_now
  
imports: import random
  from datetime import datetime, timezone
  import pytest
  from neptune.metadata_containers import MetadataContainer
  from tests.e2e.base import AVAILABLE_CONTAINERS, BaseE2ETest, fake
label_desc: Use image node_id 2 for calling the TestAtoms obj's underlying member method code with example usage: obj.test_simple_assign_datetime(container) without return types