``` import cPickle as pickle import xray import numpy as np import pandas as pd foo_values = np.random.RandomState(0).rand(3,4) times = pd.date_range('2001-02-03', periods=3) ds = xray.Dataset({'time': ('time', times), 'foo': (['time', 'space'], foo_values)}) with open('mypickle.pkl', 'w') as f: pickle.dump(ds, f) with open('mypickle.pkl') as f: myds = pickle.load(f) myds ``` This code results in: `<repr(<xray.dataset.Dataset at 0x7f95a3290d90>) failed: AttributeError: mapping>`