def METHOD_NAME(self):
    filename = join(data_dir(), 'energy.h5')
    ds = DataSet(filename)
    elec = ds.buildings[1].elec
    df = next(elec.load())
    self.assertEqual(len(df), 13)
    df = next(elec.load(chunksize=5))
    self.assertEqual(len(df), 5)
    df = next(elec.load(physical_quantity='energy'))
    self.assertEqual(len(df), 13)
    self.assertEqual(df.columns.levels, [['energy'], ['reactive']])
    df = next(elec.load(ac_type='active'))
    self.assertEqual(df.columns.levels, [['power'], ['active']])