Plotting Imag(Y11+Y12) in Cadence Virtuoso/Spectre

I want to plot Imag(Y11+Y12) in Cadence Virtuoso/Spectre.

Plotting them individually is easy, but I want the imaginary of their sum, which is more difficult.

I am using an old version : IC5.14. How would I plot this ?

Simply use Skill function, imag().
That?s all.