sympy/sympy — pull request #2973 by skirpichev (2014-02-27 09:46:53+00:00)
Title: Fix issue 1973: hash(Integer) should return the int

http://code.google.com/p/sympy/issues/detail?id=1973

@smichr, please take look on changes in add.py. \_addsort and \_mulsort were introduced by 8942676. Why cmp_to_key(Basic.compare) wasn't used as a key in both places?