old_contents: import os
  
  
  class Config(object):
      """
      The shared configuration settings for the flask app.
      """
      PROJECT_ROOT = os.path.abspath(os.path.join(os.path.dirname(__file__)))
      CSRF_ENABLED = True
      CSRF_SESSION_KEY = "supersecretpassword"
      SECRET_KEY = 'supersecretpassword'
  
  
  class ProdConfig(Config):
      """
      Setup the production configuration for the flask app.
  
      Args:
          Config (object): Inherit the default shared configuration settings.
      """
      ENV = 'prod'
      DEBUG = False
      heroku = os.environ.get('DATABASE_URL')
      if heroku:
          SQLALCHEMY_DATABASE_URI = heroku
      else:
          SQLALCHEMY_DATABASE_URI = 'postgresql://localhost/example'
  
  
  class DevConfig(Config):
      """
      Setup the development configuration for the flask app.
  
      Args:
          Config (object): Inherit the default shared configuration settings.
      """
      ENV = 'dev'
      DEBUG = True
      DB_PATH = os.path.join(Config.PROJECT_ROOT, 'dev.db')
      SQLALCHEMY_DATABASE_URI = 'sqlite:///{0}'.format(DB_PATH)
  
new_contents: import os
  
  
  class Config(object):
      """
      The shared configuration settings for the flask app.
      """
      PROJECT_ROOT = os.path.abspath(os.path.join(os.path.dirname(__file__)))
      CSRF_ENABLED = True
      CSRF_SESSION_KEY = "supersecretpassword"
      SECRET_KEY = 'supersecretpassword'
  
  
  class ProdConfig(Config):
      """
      Setup the production configuration for the flask app.
  
      Args:
          Config (object): Inherit the default shared configuration settings.
      """
      ENV = 'prod'
      DEBUG = False
      SQLALCHEMY_DATABASE_URI = os.environ.get('DATABASE_URL',
                                               'postgresql://localhost/example')
  
  
  class DevConfig(Config):
      """
      Setup the development configuration for the flask app.
  
      Args:
          Config (object): Inherit the default shared configuration settings.
      """
      ENV = 'dev'
      DEBUG = True
      DB_PATH = os.path.join(Config.PROJECT_ROOT, 'dev.db')
      SQLALCHEMY_DATABASE_URI = 'sqlite:///{0}'.format(DB_PATH)
  
subject: Use environment db url, otherwise a service specific one.