What is '1butter' in this Wiener Filter code?

MATLAB doesnt recognise the 1butter in this code of Wiener Filtering on an image in MATLAB

[Rena Berman]

(Answers Dev) Restored edit

Answer 1

[Dave B]

I'm guessing it's just supposed to be butter, there's no function in MATLAB called 1butter, and there couldn't be because numbers can't be at the beginning of a function name, and I doubt it's lbutter (i.e. a lowercase L), and the function signature/usage looks just like butter. I think it's a typo.