sympy/sympy — pull request #1214 by Botouls (2012-04-06 06:22:17+00:00)
Title: issue #3206 : Abs()

I fixed the issue when the Abs function is called with another Abs as parameter it returns something like Abs(Abs(expression)).
With this fix if you enter, for example, Abs(Abs(2*x)) it should return Abs(2*x) instead of Abs(Abs(2*x)) as it did before.