investigate trailing space in assignment name if number is blank

Guessing the trailing spaces should actually be removed, but, should probably investigate if that's true.  Noticed during testing for published API compliance - notice trailing spaces on a15, b15 (number is blank)

`assignments:['AC 103', 'AD 111', 'a15 ', 'b15 ', 'AC:1 103', 'AD:1 111', 'a15 ']`