def is_array_field(test_dataframe, test_field):
    """Tests if the column test_field in test_dataframe is an array field
    :param test_dataframe: dataframe to test
    :param test_field: column name to test
    :return: True or False
    """
    if test_dataframe.empty:
        raise ValueError("No data saved from dataset - DataFrame is empty")
    test_value = test_dataframe[test_field][0]
    return (hasattr(test_value, "__len__") and not isinstance(test_value, (str, bytes)))