Fix Cube docstring
Fix Cube docstring

bretthandrews/marvin,sdss/marvin,sdss/marvin,bretthandrews/marvin,bretthandrews/marvin,albireox/marvin,albireox/marvin,albireox/marvin,albireox/marvin,sdss/marvin,bretthandrews/marvin,sdss/marvin