std::map reference removed

Author: VioletGiraffe

container/set_operations.hpp

@@ -4,7 +4,6 @@
 
 #include <algorithm>
 #include <iterator>
-#include <map>
 #include <numeric>
 #include <set>
 #include <type_traits>
@@ -129,12 +128,6 @@ template <typename ItemType>
 	return set;
 }
 
-template <typename KeyType, typename ValueType>
-[[nodiscard]] const std::map<KeyType, ValueType>& uniqueElements(const std::map<KeyType, ValueType>& map)
-{
-	return map;
-}
-
 template <template<typename...> class OutputContainerType, class ContainerType1, class ContainerType2, typename ComparatorType = std::less<>>
 [[nodiscard]] OutputContainerType<typename ContainerType1::value_type, std::allocator<typename ContainerType1::value_type>>
  setTheoreticDifference(