i1 : h = new MutableHashTable from {} o1 = MutableHashTable{} o1 : MutableHashTable
i2 : straighten({{3,4}, {1,2}}, h)
i3 : h#{{3,4}, {1,2}} -- get the coefficients o3 = HashTable{{{1, 2}, {3, 4}} => 1} o3 : HashTable