A=has_feature(@,S)?

S."@"=2?
A=has_feature(@,S)?
.
A=s(q,w,e,f=>r)?
has_feature(1,A)?

has_feature("1",A)?

has_feature(4,A)?
X=str2psi("2")?
has_feature(X,A)?


X=str2psi("4")?
has_feature(X,A)?
.
A = s(q,w,e,f => r)?
has_feature(f,A)?

has_feature(e,A)?
.
