Can't handle Piecewise function

If you try to calculate `1 / pi integral_(-pi)^pi x^2 cos n x dif x`, it will return `= Piecewise((2 (pi sin(pi n) + 2 cos(pi n) / n - 2 n^-2 sin(pi n) / pi) / n, n > -oo or n > 0 and n > -oo or n < oo and n > 0 or n < 0 and n < 0 or n < oo), (2/3 pi^2, True))`, while typst doesn't understand `Piecewise`.