drop
    :: KnownNat n
    => Proxy (n::Nat)
    -> SizedList (m+n) a
    -> SizedList m a
drop p = snd . splitAt p
drop
    :: KnownNat n
    => Proxy (n::Nat)
    -> SizedList (m+n) a
    -> SizedList m a
drop p = snd . splitAt p
drop p = snd . splitAt p