A convenience to define a lens that can be piped into with |>.

deflens some_lens(foo, bar), do: some_lens_combination(foo, bar)

Is equivalent to:

def some_lens(foo, bar), do: some_lens_combination(foo, bar)
def some_lens(previous, foo, bar), do: Lens.seq(previous, some_lens_combination(foo, bar))

Same as deflens but creates private functions instead.