old_contents: import os
  
  basedir = os.path.abspath(os.path.dirname(__file__))
  
  class Config:
      """ Base configuration with values used in all configurations. """
  
      SERVER_NAME = "localhost:5000"
      SECRET_KEY = os.getenv("SECRET_KEY")
      SQLALCHEMY_RECORD_QUERIES = True
      SQLALCHEMY_TRACK_MODIFICATIONS = True
  
  
  class DevelopmentConfig(Config):
      """
      Development configuration.
  
      Activates the debugger and uses the database specified
      in the DEV_DATABASE_URL environment variable.
  
      """
  
      DEBUG = True
      SQLALCHEMY_DATABASE_URI = os.getenv("DEV_DATABASE_URL")
  
  
  class TestingConfig(Config):
      """
      Testing configuration.
  
      Sets the testing flag to True and uses the database
      specified in the TEST_DATABASE_URL environment variable.
  
      """
  
      TESTING = True
      SQLALCHEMY_DATABASE_URI = os.getenv("TEST_DATABASE_URL")
  
  
  config = {
      "development": DevelopmentConfig,
      "testing": TestingConfig,
      "default": DevelopmentConfig
  }
new_contents: import os
  
  basedir = os.path.abspath(os.path.dirname(__file__))
  
  class Config:
      """ Base configuration with values used in all configurations. """
  
      SERVER_NAME = "localhost:5000"
      SECRET_KEY = os.getenv("MYDICTIONARY_SECRET_KEY")
      SQLALCHEMY_RECORD_QUERIES = True
      SQLALCHEMY_TRACK_MODIFICATIONS = True
  
  
  class DevelopmentConfig(Config):
      """
      Development configuration.
  
      Activates the debugger and uses the database specified
      in the DEV_DATABASE_URL environment variable.
  
      """
  
      DEBUG = True
      SQLALCHEMY_DATABASE_URI = os.getenv("MYDICTIONARY_DEV_DATABASE_URL") or \
                                "sqlite:///" + os.path.join(basedir, "dev_database.sqlite")
  
  
  class TestingConfig(Config):
      """
      Testing configuration.
  
      Sets the testing flag to True and uses the database
      specified in the TEST_DATABASE_URL environment variable.
  
      """
  
      TESTING = True
      SQLALCHEMY_DATABASE_URI = os.getenv("MYDICTIONARY_TEST_DATABASE_URL") or \
                                "sqlite:///" + os.path.join(basedir, "test_database.sqlite")
  
  
  config = {
      "development": DevelopmentConfig,
      "testing": TestingConfig,
      "default": DevelopmentConfig
  }
subject: Change environment variable names and add placeholders