old_contents: from core import State, Orbit
  import constants
  import const
  import ephem
  import examples
  import frames
  import orbit
  import state
  import time
  import util
  import vis
  
new_contents: from core import State, Orbit
  import const
  import ephem
  import examples
  import frames
  import orbit
  import state
  import time
  import util
  import vis
  
subject: Fix import.