old_contents: #! /usr/bin/env python
  
  import os
  
  from cyclus_tools import run_cyclus
  from tests_list import sim_files
  
  def main():
      """Creates reference databases. Assumes that cyclus is included into PATH.
      """
      cwd = os.getcwd()
  
      # Run cyclus
      run_cyclus("cyclus", cwd, sim_files)
  
  if __name__ == "__main__": main()
  
new_contents: #! /usr/bin/env python
  
  import os
  
  from cyclus_tools import run_cyclus
  from testcases import sim_files
  
  def main():
      """Creates reference databases. Assumes that cyclus is included into PATH.
      """
      cwd = os.getcwd()
  
      # Run cyclus
      run_cyclus("cyclus", cwd, sim_files)
  
  if __name__ == "__main__": main()
  
subject: Correct import statement after renaming test_lists.py to testcases