def _dataframe_from_txt(reader):
    return pd.read_csv(reader, header=None, sep="\n", encoding='utf-8-sig')
`viewport` is in coordinates of the layout manager.
dataset/ETHPy150Open Azure/Azure-MachineLearning-ClientLibrary-Python/azureml/serialization.py/_dataframe_from_txt--crossover with--dataset/ETHPy150Open kivy/kivy/kivy/uix/recycleview/layout.py/RecycleLayoutManagerBehavior.compute_visible_views