Fix type, returned by polylog(s, 0)
Fix type, returned by polylog(s, 0)

This solves the problem, mentioned in
https://groups.google.com/forum/?fromgroups=#!topic/sympy/weBJjkkW5EA

In [1]: from sympy import *
In [2]: from sympy.abc import x, a
In [3]: integrate(log(x)/(1 - x), (x, 0, 1))
Out[3]:
        ⎛     ⅈ⋅π⎞
-polylog⎝2, -ℯ   ⎠
In [4]: _.n()
Out[4]: -1.64493406684823

Looks to be a correct answer, but more ugly
then Mathematica's one:

In[1]:= Integrate[Log[x]/(1 - x), {x, 0, 1}]
Integrate[Log[x]/(1 - x), {x, 0, 1}]
Out[1]=
   2
-Pi
----
 6
In[2]:= -PolyLog[2, -Exp[I Pi]]
-PolyLog[2, -Exp[I Pi]]
Out[2]=
   2
-Pi
----
 6

diofant/diofant,skirpichev/omg