Deduce the template parameter KEY from the value_type of the initializer_list supplied to the constructor of unordered_multiset. This deduction guide does not participate unless the supplied allocator is convertible to bsl::allocator<KEY>.
Declared in <bslstl_unorderedmultiset.h>
template<
class KEY,
class ALLOC,
class DEFAULT_ALLOCATOR = bsl::allocator<KEY>>
requires bsl::is_convertible_v<ALLOC *, DEFAULT_ALLOCATOR>
unordered_multiset<KEY>(
std::initializer_list<KEY>,
ALLOC*) -> unordered_multiset<KEY>;