[Boost-users] unordered_set insert returns const_iterator ?

Hi while i am using boost unordered_set , and insert a new key value pair, it returns the iterator as a const one. In fact when i looked at the code, the iterator is a typedef to implementation::const_iterator ... so there is no way to gen an mutable iterator from the set, including begin() and end() is it a standard behavior or i am missing something ? thanks abir