code: def create(model_config, url, local_dir, sequence_length=64, batch_size=64, train_val_split=0.8):
      
      if not os.path.isabs(local_dir):
          local_dir = model_config.project_data_dir(local_dir)
  
      return TextUrlSource(
          url,
          absolute_data_path=local_dir,
          sequence_length=sequence_length,
          batch_size=batch_size,
          train_val_split=train_val_split,
      )
docs: Vel factory function