Create and Visualize Discriminant Analysis Classifier linear function problems to plot or create

Hello!

I have problems with this part:4

f = @(x1,x2) K + L(1)*x1 + L(2)*x2;
figure %create 2D plot
di2 = feval(f)
%Not enough input arguments.
%Error in @(x1,x2)K+L(1)*x1+L(2)*x2

it cames from the code in: https://de.mathworks.com/help/stats/create-and-visualize-discriminant-analysis-classifier.html

originally is with fimplicit, but in my version of MTL dosent work, I follow the steps as mention in the link, but not resault.

Any idea will be appreciated!

Thanks