bool operator()( const KEY& lhs, const KEY& rhs ) const
{
boost::shared_ptr<KEY::element_type> shared_lhs = lhs.lock();
boost::shared_ptr<KEY::element_type> shared_rhs = rhs.lock();
return *shared_lhs < *shared_rhs;
}
size_t operator()( const KEY& key ) const
{
boost::shared_ptr<KEY::element_type> shared_key = key.lock();
return static_cast<size_t>( *shared_key );
}