Typeclass proving that it is possible to send a tree of effects R into another tree of effects U
send[Option1, Fx.fx3[Option1, Option2, Option3], Int](Option1(1)).
into[Fx.fx5[Option1, Option2, Option3, Option4, Option5]]
should work because all the effects of the first stack are present in the second
Note: some implicit definitions are probably missing in some cases