(examples-for ⋃

("returns a single arg"
 (⋃ '(a b c))
 (a b c))

("returns union of two args"
 (⋃ '(a b c) '(a b d))
 (a b c d))

("returns union of arg and nil"
 (⋃ '(a b c) nil)
 (a b c))

("returns union of three args"
 (⋃ '(a b c d e) '(a b c d f) '(z b c d g))
 (a b c d e f z g))

("returns union of arg nil arg"
 (⋃ '(a b c d e) nil '(z b c d g))
 (a b c d e z g))

("returns union of four args"
 (⋃ '(a b c d e) '(a b c d f) '(z b d c g) '(z y g c d))
 (a b c d e f z g y)))