      "\n",
      "    def __init__(self, num_stacks, stack_size):\n",
      "        self.num_stacks = num_stacks\n",
      "        self.stack_size = stack_size\n",
      "        self.stack_pointers = [-1] * num_stacks\n",
      "        self.stack_array = [None] * num_stacks * stack_size\n",
      "\n",
      "    def abs_index(self, stack_index):\n",
      "        return stack_index * self.stack_size + self.stack_pointers[stack_index]\n",
      "\n",
      "    def push(self, stack_index, data):\n",
 
</s>
    "        self.stack_pointers = [-1] * self.num_stacks\n",
    "        self.stack_array = [None] * self.num_stacks * self.stack_size\n",
      "\n",
      "    def __init__(self, num_stacks, stack_size):\n",
      "        self.num_stacks = num_stacks\n",
      "        self.stack_size = stack_size\n",
    "        self.stack_pointers = [-1] * self.num_stacks\n",
    "        self.stack_array = [None] * self.num_stacks * self.stack_size\n",
    "        self.stack_pointers = [-1] * self.num_stacks\n",
    "        self.stack_array = [None] * self.num_stacks * self.stack_size\n",
      "\n",
      "    def abs_index(self, stack_index):\n",
      "        return stack_index * self.stack_size + self.stack_pointers[stack_index]\n",
      "\n",
      "    def push(self, stack_index, data):\n",
keep keep keep keep replace replace keep keep keep keep keep
 Update queue from stacks challenge (#111)

Update test cases and __init__ method.
stacks_queues/n_stacks/n_stacks_solution.ipynb