code: def imgwriteincr(fn: Path, imgs, imgslice):
      
      if isinstance(imgslice, int):
          if imgslice and not (imgslice % 2000):
              print(f'appending images {imgslice} to {fn}')
  
      if isinstance(fn, Path):
          # avoid accidental overwriting of source file due to misspecified command line
          assert fn.suffix == '.h5', 'Expecting to write .h5 file'
  
          with h5py.File(fn, 'r+') as f:
              f['/rawimg'][imgslice, :, :] = imgs
      elif isinstance(fn, h5py.File):
          f['/rawimg'][imgslice, :, :] = imgs
      else:
          raise TypeError(
              f'{fn} must be Path or h5py.File instead of {type(fn)}')
docs: writes HDF5 huge image files in increments