Python Django import export before_import_row自动创建对象（如果对象不存在）

在使用Django import-export时，我面临着当前的问题：

在我的admin.py中：

class QuestionResource(resources.ModelResource):
category = fields.Field(
        column_name='category',
        attribute='category',
        widget=ForeignKeyWidget(Category, 'category')
    )

class Meta:
    model = Question
    fields = ['id', 'question', 'category', 'answer',]
    # exclude = ('created', 'modified', 'verified', 'count', 'user_created')

# PREVIOUS THINGS I TRIED: 

# def _post_import(model, **kwargs):
#   query = self.fields['category']
#   category = Question.objects.get_or_create(category=query)
#   return category

# def before_import(self, dataset, dry_run, *args, **kwargs):
#   query = self.fields['category']
#   for q in query:
#       Category.objects.get_or_create(category=q)

# def before_import_row(row, *args, **kwargs):
#   category = self.fields['category']
#   Category.objects.get_or_create(category=category)

def before_import_row(row, *args, **kwargs):
    category = row.fields['category']
    Category.objects.get_or_create(category=category)

正如你所看到的，我添加了以前尝试过的注释。我收到的错误是：

Errors

Line number: 5 - Category matching query does not exist.
Pokemon, 9526, Is er een voorvak?, Ja, bij de Alpha is een voorvak.

Traceback (most recent call last):
File "/Users/iam-tony/.envs/lib/python3.6/site-packages/import_export/resources.py", line 457, in import_row
self.import_obj(instance, row, dry_run)
File "/Users/iam-tony/.envs/lib/python3.6/site-packages/import_export/resources.py", line 329, in import_obj
self.import_field(field, obj, data)
File "/Users/iam-tony/.envs/lib/python3.6/site-packages/import_export/resources.py", line 316, in import_field
field.save(obj, data, is_m2m)
File "/Users/iam-tony/.envs/lib/python3.6/site-packages/import_export/fields.py", line 115, in save
cleaned = self.clean(data)
File "/Users/iam-tony/.envs/lib/python3.6/site-packages/import_export/fields.py", line 69, in clean
value = self.widget.clean(value, row=data)
File "/Users/iam-tony/.envs/lib/python3.6/site-packages/import_export/widgets.py", line 334, in clean
return self.get_queryset(value, row, *args, **kwargs).get(**{self.field: val})
File "/Users/iam-tony/.envs/lib/python3.6/site-packages/django/db/models/query.py", line 403, in get
self.model._meta.object_name
questions.models.DoesNotExist: Category matching query does not exist.

我错过了什么？我似乎找不到这方面的任何文档（或者有，但我不明白）

提前谢谢

什么是类别#类别字段？类别的名称？一根绳子

尝试将该字段重置为所创建类别的主键：

def before_import_row(self, row, **kwargs):
    name = row.get('category')
    (cat, _created) = Category.objects.get_or_create(name=name)
    row['category'] = cat.id