class_docstr: Handler that saves input checkpoint to the Neptune server.
  
  Args:
      neptune_logger: an instance of
          NeptuneLogger class.
  
  .. Note ::
  
      NeptuneSaver is currently not supported on Windows.
  
  Examples:
      .. code-block:: python
  
          from ignite.contrib.handlers.neptune_logger import *
  
          # Create a logger
          # We are using the api_token for the anonymous user neptuner but you can use your own.
  
          npt_logger = NeptuneLogger(
              api_token="ANONYMOUS",
              project_name="shared/pytorch-ignite-integration",
              experiment_name="cnn-mnist", # Optional,
              params={"max_epochs": 10}, # Optional,
              tags=["pytorch-ignite","minst"] # Optional
          )
  
          ...
          evaluator = create_supervised_evaluator(model, metrics=metrics, ...)
          ...
  
          from ignite.handlers import Checkpoint
  
          def score_function(engine):
              return engine.state.metrics["accuracy"]
  
          to_save = {"model": model}
  
          # pass neptune logger to NeptuneServer
  
          handler = Checkpoint(
              to_save,
              NeptuneSaver(npt_logger), n_saved=2,
              filename_prefix="best", score_function=score_function,
              score_name="validation_accuracy",
              global_step_transform=global_step_from_engine(trainer)
          )
  
          evaluator.add_event_handler(Events.COMPLETED, handler)
  
          # We need to close the logger when we are done
          npt_logger.close()
  
  For example, you can access model checkpoints and download them from here:
  https://ui.neptune.ai/o/shared/org/pytorch-ignite-integration/e/PYTOR1-18/charts
code: def __init__(self, neptune_logger: NeptuneLogger):
      self._logger = neptune_logger
  
imports: import tempfile
  import warnings
  from typing import Any, Callable, List, Mapping, Optional, Union
  import torch
  from torch.optim import Optimizer
  import ignite.distributed
  from ignite import __version__
  from ignite.contrib.handlers.base_logger import BaseLogger, BaseOptimizerParamsHandler, BaseOutputHandler, BaseWeightsScalarHandler
  from ignite.engine import Engine, Events
  from ignite.handlers import global_step_from_engine
  from ignite.handlers.checkpoint import BaseSaveHandler
label_desc: Use image node_id 1 to create a new NeptuneSaver object from inherited base classes: BaseSaveHandler with example: obj = NeptuneSaver(neptune_logger)