old_contents: import os
  
  
  class Config(object):
      DEBUG = False
      TESTING = False
      BASE_DIR = os.path.abspath(os.path.dirname(__file__))
      SQLALCHEMY_DATABASE_URI = os.environ['DATABASE_URL']
      SQLALCHEMY_TRACK_MODIFICATIONS = True
  
  
  class ProductionConfig(Config):
      DEBUG = False
  
  
  class StagingConfig(Config):
      DEBUG = True
      DEVELOPMENT = True
  
  
  class DevelopmentConfig(Config):
      DEBUG = True
      DEVELOPMENT = True
  
  
  class TestingConfig(Config):
      TESTING = True
  
new_contents: import os
  
  
  class Config(object):
      DEBUG = False
      TESTING = False
      SQLALCHEMY_DATABASE_URI = os.environ['DATABASE_URL']
      SQLALCHEMY_TRACK_MODIFICATIONS = True
  
  
  class ProductionConfig(Config):
      DEBUG = False
  
  
  class StagingConfig(Config):
      DEBUG = True
      DEVELOPMENT = True
  
  
  class DevelopmentConfig(Config):
      DEBUG = True
      DEVELOPMENT = True
  
  
  class TestingConfig(Config):
      TESTING = True
  
subject: Remove useless BASE_DIR config