Python 3必须是str，而不是int

Question

尝试将列表添加到词典并计数。

FileTextBox.SelectionStart = FileTextBox.Text.Length;
FileTextBox.SelectionLength = 0;

始终获取错误“ TypeError：必须为str，而不是int inline：

    inventory = {"rope": '2', "torch": '4', "sword": '1', "bow": '1', "arrow": '10'}
dragon_loot = ['dagger', 'gold coin', 'gold coin', 'arrow', 'rope']

def inventory_hero(inv):
    print("item | quantity")
    print("----------")
    total_quantity = 0
    for k, v in inv.items():
        print(str(k) + " : " + str(v))
        total_quantity += int(v)
    print("----------")
    print("total: " + str(total_quantity))

def add_to_inventory(inv, loot_from):
    for i in loot_from:
        inv.setdefault(i, 0)
        inv[i] += 1

inventory_hero(inventory)
add_to_inventory(inventory, dragon_loot)
inventory_hero(inventory)

尝试计算字符串中的字符，带有+ =的所有内容都可以正常工作，但字典始终出错。