try:
    import pytorch_lightning
except ImportError:
    # pytorch_lightning isn't installed, don't import this package.
    pass
else:
    from .histogram import Histogram
    from .tensorboard_add_classification import TensorBoardAddClassification
    from .tensorboard_add_ss import TensorBoardAddSS
    from .tensorboard_add_depth import TensorBoardAddDepth
    from .model_checkpoint import ModelCheckpoint
