code: def get_str(self, key, default=None):
          
          if key:
              for provider in self.providers:
                  value = provider.get_str(key)
                  if value is not None:
                      return value
  
          return default
docs: Args:
              key (str | unicode | None): Key to lookup
              default (str | unicode | None): Default to use if key is not configured
  
          Returns:
              (str | None): Value of key, if defined