new_contents:   #appengine_config.py
    """`appengine_config` gets loaded when starting a new application instance."""
  import sys
  import os.path
  # add `lib` subdirectory to `sys.path`, so our `main` module can load
  # third-party libraries.
  sys.path.insert(0, os.path.join(os.path.dirname(__file__), 'lib'))
  
subject: Create appengine_config.py