docs: def load(self):
          """
          Load user configuration based on settings.
          """
  
          # Must reverse because we want the sources assigned to higher-up Config instances
          # to overrides sources assigned to lower Config instances.
          for section in reversed(list(self.iter_sections(recursive=True, key=None))):
              if section.is_config:
                  section.load()
  
          for source in self.settings.load_sources:
              adapter = getattr(self, _get_persistence_adapter_for(source))
              if adapter.store_exists(source):
                  adapter.load(source)