code: def populate_all_metadata():
      
      for Metadata in registry.values():
          InstanceMetadata = Metadata._meta.get_model('modelinstance')
          if InstanceMetadata is not None:
              for model in Metadata._meta.seo_models:
                  populate_metadata(model, InstanceMetadata)
docs: Create metadata instances for all models in seo_models if empty.
          Once you have created a single metadata instance, this will not run.
          This is because it is a potentially slow operation that need only be
          done once. If you want to ensure that everything is populated, run the
          populate_metadata management command.