[dump] void_ptr => 0x7ffd06586204
[dump] (unordered_map<int, int>{{4, 6}, {2, 6}, {4, 3}}) => { 2: 6, 4: 6 }
[dump] unordered_multimap1 => {
         'b' (1): [ 20 ],
         'c' (1): [ 30 ],
         'a' (2): [ 10, 40 ]
       }
[dump] (unordered_set{3, 1, 4, 1, 5}) => { 5, 4, 1, 3 }
[dump] unordered_multiset1 => { 4 (1), 3 (1), 1 (2) }
