* ('a,'r) cont not ('a) cont---we can't match the type ('a) m that
* Tree_monadizer expects in its parameter. So we have to make a different
* Tree_monadizer2 that takes a ('a,'x) m type constructor in its
* ('a,'r) cont not ('a) cont---we can't match the type ('a) m that
* Tree_monadizer expects in its parameter. So we have to make a different
* Tree_monadizer2 that takes a ('a,'x) m type constructor in its