allow for usage of inner_key when list is expected

[djarecka]

I had an issue when using inner_key to support any_of or exactly_one_of, because there was no support for list, so I added it to work with example like this:

class	slot	range exactly_one_of	  range any_of	      desc
>class	slot	exactly_one_of	          any_of	      description
>		inner_key: range          inner_key: range	
ClassA				                              class A
ClassA	slot_a	int|string	  	                      slot a
ClassA	slot_b		                  int|string	      slot b

If there is other way that I should represent any_of or exactly_one_of please let me know, couldn't find an example