sympy/sympy — pull request #1537 by jrioux (2012-09-20 09:06:37+00:00)
Title: expand(trig=True) issue.

Delay evaluation until _eval_expand_trig is called.

This fixes issue 3403: 'Mul' object has no attribute '_eval_expand_trig'
http://code.google.com/p/sympy/issues/detail?id=3403