//Wald检验代码
xsmle y x1 x2 x3 x4 ,wmat(w) model(sdm) robust nolog effects fe
test [Wx]x1=[Wx]=[Wx]x3=[Wx]x4=0
testnl([Wx]x1=-[Spatial]rho*[Main]x1)([Wx]x2=-[Spatial]rho*[Main]x2)([Wx]x3=-[Spatial]rho*[Main]x3)([Wx]x4=-[Spatial]rho*[Main]x4)

//运行结果
. test [Wx]x1=[Wx]=[Wx]x3=[Wx]x4=0
Wx not found
r(111);

求助各位大神，这种情况该怎么解决呢？？？？
stata小白真诚求助