# python equivalent of T(x,y)=(x*y,x+y) ?

In sage command line, I can write T(x,y) = (x*y,x+y) and can apply T.diff() to compute Jacobian.

But when I write the same in python, it says you can not assign to a function.

Does anyone know what I should write in python for T(x,y)=(x*y,x+y)?

I'm not sure if this belongs on ask.sagemath... after all, this is a Sage help site. Or am I missing something?