Thus f should be a function of one variable v which returns a new value v' for the key k in the resulting hash table.
i1 : x = new HashTable from {a => 1, b => 2, c => 3} o1 = HashTable{a => 1} b => 2 c => 3 o1 : HashTable
i2 : applyValues(x, v -> v + 100) o2 = HashTable{a => 101} b => 102 c => 103 o2 : HashTable
See also applyPairs and applyKeys.