Implement an index type for Multiset.
Implement an index type for Multiset.

IngmarStein/Set,IngmarStein/Set,madbat/Set,natecook1000/Set,robrix/Set,natecook1000/Set,IngmarStein/Set,natecook1000/Set,robrix/Set,robrix/Set,madbat/Set,madbat/Set