# "Curve" function error: 'list' object is not callable

Hello!

I am trying to work with the curve constructor (particularly affine curves) in sage using their built in functions. I am using this page as reference: https://doc.sagemath.org/html/en/refe...

But when I try to define curves like below I get the `'list' object not callable`

error message every time, even when I copy and paste code from the sage reference manual.

`A.<x,y> = AffineSpace(QQ, 2)`

`C = Curve(x^2 + y^2 -1)`

I understand that it probably thinks `Curve`

is a list or something, but I'm not sure how to fix it?

Any help would be greatly appreciated!