old_contents: import image
  import reference
  import fmri
  import statistics
  import visualization
  
  import data.cache
  data.cache.suffix = 'nipy'
  
new_contents: import matplotlib
  # ensure that matplotlib is using numpy for its numeric backend
  matplotlib.rcParams['numerix'] = 'numpy'
  
subject: remove unnecessary imports, remove cache suffix setting, ensure matplotlib uses numpy.