_hashable_content should return a tuple.
You can merge this Pull Request by running:
git pull https://github.com/Krastanov/sympy subs_hashable_content
Or you can view, comment on it, or merge it online at:
https://github.com/sympy/sympy/pull/1437
-- Commit Summary --
* Correct the _hashab
This makes all cache retrievals faster, eg:
before
In [1]: %timeit Pow(y, 2)
10 loops, best of 3: 9.8 us per loop
after
In [1]: %timeit Pow(y, 2)
10 loops, best of 3: 7.5 us per loop
You can merge this Pull Request by running:
git pull https://github.com/rlamy/sympy caching
Or you ca
