text: #coding=utf-8
  
  import os
  
  
  class Config:
      HOST = os.getenv('HOST', '0.0.0.0')
  
      PORT = int(os.getenv('PORT', '5000'))
  
      SQLALCHEMY_DATABASE_URI = os.getenv('SQLALCHEMY_DATABASE_URI', 'sqlite:///:memory:')
  
      SQLALCHEMY_TRACK_MODIFICATIONS = True
  
      TESTING = False
  
      DEBUG = False
  
  
  class DevelopmentConfig(Config):
      DEBUG = True
  
      SQLALCHEMY_DATABASE_URI = 'sqlite:///dev.db'
  
  
  class TestingConfig(Config):
      TESTING = True
  
  
  class ProductionConfig(Config):
      pass
  
  
  def get_config(config_name):
      return {
          'development': DevelopmentConfig,
          'testing': TestingConfig,
          'production': ProductionConfig,
      }.get(config_name)
  