Create a multiset having the same value as the specified original object that uses the specified basicAllocator to supply memory. Use a copy of original.key_comp() to order the keys contained in this multiset. This method requires that the (template parameter) type KEY be copy‐insertable into this multiset (see {Requirements on KEY}). Note that a bslma::Allocator * can be supplied for basicAllocator if the (template parameter) type ALLOCATOR is bsl::allocator (the default).