-- | @project@s a single fields type out of a disbanded data type.
project :: (Codomain sum ~ Codomain dc, Partition sum (N dc) (sum :-: N dc)) =>
           sum -> Either dc (sum :-: N dc)
project = TypeSums.project
project :: (Codomain sum ~ Codomain dc, Partition sum (N dc) (sum :-: N dc)) =>
           sum -> Either dc (sum :-: N dc)
project = TypeSums.project
project = TypeSums.project