old_contents: 
  from niimg_conversions import is_a_niimg, _get_shape, _repr_niimgs, \
          copy_niimg, check_niimg, concat_niimgs, check_niimgs
  
  from numpy_conversions import as_ndarray
  
  from cache_mixin import CacheMixin
  
  
new_contents: 
  from .niimg_conversions import is_a_niimg, _get_shape, _repr_niimgs, \
          copy_niimg, check_niimg, concat_niimgs, check_niimgs
  
  from .numpy_conversions import as_ndarray
  
  from .cache_mixin import CacheMixin
  
  
subject: Fix imports to local paths