sympy/sympy — pull request #8574 by rwst (2014-12-07 15:31:21+00:00)
Title: add _sage_() method to many Functions; fixes part of #3444

This adds `_sage_` methods to those symbolic functions where it's a trivial three-liner. Important missing "functions" needing this are `diff`, `integral`, and `hyper`; they should come in a later commit. Part of #3444