code: def load(obj, env=None, silent=True, key=None, filename=None):
      
      # Load data from your custom data source (file, database, memory etc)
      # use `obj.set(key, value)` or `obj.update(dict)` to load data
      # use `obj.logger.debug` to log your loader activities
      # use `obj.find_file('filename.ext')` to find the file in search tree
      # Return nothing
  
      # This loader reads the .sff file // Stupid File Format
      keys = []
      values = []
      found_file = obj.find_file("settings.sff")
      if not found_file:
          obj.logger.debug("Cannot find settings.sff")
          return
  
      with open(found_file) as settings_file:
          for line in settings_file.readlines():
              if line.startswith("#"):
                  continue
              if line.startswith("KEYS:"):
                  keys = line.strip("KEYS:").strip("\n").split(";")
              if line.startswith("VALUES:"):
                  values = line.strip("VALUES:").strip("\n").split(";")
  
      # // PLEASE DON'T USE THIS SFF file format :)
  
      data = dict(zip(keys, values))
  
      if key:
          value = data.get(key.lower())  # sff format have lower case keys
          obj.logger.debug("Sff loader: %s:%s", key, value)
          obj.set(key, value)
      else:
          obj.logger.debug("Sff loader: loading: {0}".format(data))
          obj.update(data)
  
      obj._loaded_files.append(found_file)
docs: Reads and loads in to "obj" a single key or all keys from source
      :param obj: the settings instance
      :param env: settings current env (upper case) default='DEVELOPMENT'
      :param silent: if errors should raise
      :param key: if defined load a single key, else load all from `env`
      :param filename: Custom filename to load (useful for tests)
      :return: None