new_contents: raise DeprecationWarning("""DEPRECATED:
  
  After Popular request and decision from the BDFL:
  `IPython.terminal.ptshell` has been moved back to `IPython.terminal.interactiveshell`
  during the beta cycle (after IPython 5.0.beta3) Sorry about that. 
  
  This file will be removed in 5.0 rc or final.
  """)
  
subject: Add a warning things have been moved back.