Change of programmation of implicit
In the former question "Calculus with formal functions: substitution?", one can obtain implicit differentiation by the following code
var('f,x,y')
y = function('y',x)
f = function('f',x,y)
f.diff(x)
which gives
D1(x, y(x))*D0(x) +D0(x, y(x))
But I use the last version ofg SageMath and I have the following error
TypeError: function() takes exactly 1 positional argument (2 given)
Is there some new way to handle this code ?