class AmazonScraperPipeline(object):
    def process_item(self, item, spider):
        item.setdefault('publisher', 'No editorial recommendation')
        item.setdefault('link', '')
        item.setdefault('posted_date', '')
        item.setdefault('title', '')

Traceback (most recent call last):
  File "/home/vlad/PycharmProjects/marakas_test_task/venv/lib/python3.8/site-packages/twisted/internet/defer.py", line 151, in maybeDeferred
    result = f(*args, **kw)
  File "/home/vlad/PycharmProjects/marakas_test_task/venv/lib/python3.8/site-packages/pydispatch/robustapply.py", line 55, in robustApply
    return receiver(*arguments, **named)
  File "/home/vlad/PycharmProjects/marakas_test_task/venv/lib/python3.8/site-packages/scrapy/extensions/feedexport.py", line 268, in item_scraped
    slot.exporter.export_item(item)
  File "/home/vlad/PycharmProjects/marakas_test_task/venv/lib/python3.8/site-packages/scrapy/exporters.py", line 243, in export_item
    values = list(self._build_row(x for _, x in fields))
  File "/home/vlad/PycharmProjects/marakas_test_task/venv/lib/python3.8/site-packages/scrapy/exporters.py", line 247, in _build_row
    for s in values:
  File "/home/vlad/PycharmProjects/marakas_test_task/venv/lib/python3.8/site-packages/scrapy/exporters.py", line 243, in <genexpr>
    values = list(self._build_row(x for _, x in fields))
  File "/home/vlad/PycharmProjects/marakas_test_task/venv/lib/python3.8/site-packages/scrapy/exporters.py", line 64, in _get_serialized_fields
    field_iter = six.iterkeys(item.fields)
AttributeError: 'NoneType' object has no attribute 'fields'