Traditionally, we have: ``` python In [3]: pandas.__version__ Out[3]: '0.18.0' In [4]: pandas.Index([1, 2]).equals([1, 2]) Out[4]: True ``` But this changed ``` python In [4]: pandas.__version__ Out[4]: '0.19.0' In [5]: pandas.Index([1, 2]).equals([1, 2]) Out[5]: False ``` Looks like it might not be intentional so FYI. (Noticed because it broke a few tests in the patsy test suite.)