docs: def _reload(self, force=False):
          """Reloads the configuration from the file and environment variables. Useful if using
          `os.environ` instead of this class' `set_env` method, or if the underlying configuration
          file is changed externally.
          """
          self._config_map = dict()
          self._registered_env_keys = set()
          self.__reload_sources(force)
          self.__load_environment_keys()
          self.verify()
          self._clear_memoization()