docs: def determine_final_config(config_module):
      """Determines the final additions and replacements.
  
      Combines the config module with the defaults.
  
      Args:
          config_module: The loaded local configuration module.
  
      Returns:
          Config: the final configuration.
      """
      config = Config(
          DEFAULT_LIBRARY_RC_ADDITIONS, DEFAULT_LIBRARY_RC_REPLACEMENTS,
          DEFAULT_TEST_RC_ADDITIONS, DEFAULT_TEST_RC_REPLACEMENTS)
  
      for field in config._fields:
          if hasattr(config_module, field):
              config = config._replace(**{field: getattr(config_module, field)})
  
      return config