code: def handle_exec(args):
      
      session_file = get_db_name(args.get('<session-file>'))
      cosmic_ray.commands.execute(session_file)
  
      return ExitCode.OK
docs: usage: cosmic-ray exec <session-file>
  
      Perform the remaining work to be done in the specified session.
      This requires that the rest of your mutation testing
      infrastructure (e.g. worker processes) are already running.