>>> test = pd.Series([np.nan, 1,3,3,1])
>>> test.interpolate()
0 NaN1 1.02 3.03 3.04 1.0dtype: float64
>>> test2 = pd.Series([np.nan, 1,3,3,1,np.nan])
>>> test2.interpolate()
0 NaN1 1.02 3.03 3.04 1.05 1.0dtype: float64