44    template <
typename ValueType>
 
   46        const std::set<ValueType>& firstContainer,
 
   47        const std::set<ValueType>& secondContainer,
 
   50    template <
typename ValueType>
 
   52        const std::set<ValueType>& firstContainer,
 
   53        const std::set<ValueType>& secondContainer);
 
   55    template <
typename ValueType, 
typename Comparator>
 
   57        const std::set<ValueType, Comparator>& firstContainer,
 
   58        const std::set<ValueType, Comparator>& secondContainer,