mvsw function with fixed effects leads to error

[resulumit]

The recently introduced function mvsw leads to an error in formulas with fixed effects.

This works:

library(fixest)

feols(mpg ~ cyl + mvsw(am, gear), data = mtcars)

Bu this fails:

feols(mpg ~ cyl + mvsw(am, gear) | vs, data = mtcars)

... with the following error message:

Error in feols(mpg ~ cyl + mvsw(am, gear) | vs, data = mtcars) : 
Error in str2lang(x) : <text>:1:39: unexpected symbol
1: mpg ~ cyl +  sw0(am, gear, am + gear) vs
                                          ^

[lrberge]

Thanks, it was a typo of mine. Now fixed + tests added.