def _get_arrays(region, x_data='energy', y_data='final'):
    """
    :param region: Region object
    :param x_data: region's column name
    :param y_data: region's column name
    :return: ndarrays of specified columns' values
    """
    if x_data in list(region.get_data()):
        x = region.get_data(column=x_data)
    else:
        x = region.get_data(column='energy')
    if y_data in list(region.get_data()):
        y = region.get_data(column=y_data)
    else:
        y = region.get_data(column='final')

    return x, y