code: def km3h5concat(input_files, output_file, n_events=None, **kwargs):
      
      from km3pipe import Pipeline    # noqa
      from km3pipe.io import HDF5Pump, HDF5Sink    # noqa
  
      pipe = Pipeline()
      pipe.attach(HDF5Pump, filenames=input_files, **kwargs)
      pipe.attach(StatusBar, every=250)
      pipe.attach(HDF5Sink, filename=output_file, **kwargs)
      pipe.drain(n_events)
docs: Concatenate KM3HDF5 files via pipeline.