Problems with diff(Sum((-1)**(n - 1)*x**n/n, (n,1,oo)).doit(),x)

[ghost]

>>> (diff(Sum((-1)**(n - 1)*x**n/n, (n,1,oo)).doit(),x)
 ⎛⎧     -1                             ⎞
 ⎜⎪    ─────       for │x│ ≤ 1 ∧ -x ≠ 1⎟
 ⎜⎪    x + 1                           ⎟
 ⎜⎪                                    ⎟
 ⎜⎪  ∞                                 ⎟
 ⎜⎪ ____                               ⎟
 ⎜⎪ ╲                                  ⎟
-⎜⎨  ╲       n  n                      ⎟
 ⎜⎪   ╲  (-1) ⋅x                       ⎟
 ⎜⎪   ╱  ────────       otherwise      ⎟
 ⎜⎪  ╱      x                          ⎟
 ⎜⎪ ╱                                  ⎟
 ⎜⎪ ‾‾‾‾                               ⎟
 ⎜⎪n = 1                               ⎟
 ⎝⎩                                    ⎠

There is a minus sign outside the left brace, I have never seen that notation
I think it would be better if the 2 conditions at the top had brackets around them,

for (│x│ ≤ 1) ∧ (-x ≠ 1)

Problem with the bottom term too