Web Scrapping - Scrapy en Python a archivo Excel

I'm trying to make web scrapping with Scrapy in Python, creating a Spider, just to get some text from a webpage and store it to an Excel file.

My spider:

import scrapy
from scrapy.spiders import Spider
from verbos.items import MercadoItem

class MercadoSpider(scrapy.Spider):
name = 'verbos'
allowed_domain = ['www.pt.bab.la']
start_urls = ['https://pt.bab.la/verbo/portugues/ser']


def parse_item(self, response):
    titles = MercadoItem()

    titles['titulo'] = response.xpath('//*[@id="conjFull"]/div[2]/div/div[2]/div[1]/div[2]/text()').extract()


    yield titles(callback=self.parse_item, dont_filter=True)

When I run it I get the .csv file but it is empty, and I get the next error message in the console:

> 2020-04-22 20:37:01 [scrapy.utils.log] INFO: Scrapy 2.0.1 started (bot: verbos)
  2020-04-22 20:37:01 [scrapy.utils.log] INFO: Versions: lxml 4.5.0.0, libxml2 2.9.5, cssselect 
  1.1.0, parsel 1.5.2, w3lib 1.21.0, Twisted 20.3.0, Python 3.7.7 (tags/v3.7.7:d7c567b08f, Mar 10 
  2020, 09:44:33) [MSC v.1900 32 bit (Intel)], pyOpenSSL 19.1.0 (OpenSSL 1.1.1g  21 Apr 2020), 
  cryptography 2.9.1, Platform Windows-10-10.0.18362-SP0
  2020-04-22 20:37:01 [scrapy.utils.log] DEBUG: Using reactor: 
  twisted.internet.selectreactor.SelectReactor
  2020-04-22 20:37:01 [scrapy.crawler] INFO: Overridden settings:
  {'BOT_NAME': 'verbos',
  'NEWSPIDER_MODULE': 'verbos.spiders',
  'SPIDER_MODULES': ['verbos.spiders']}
  2020-04-22 20:37:01 [scrapy.extensions.telnet] INFO: Telnet Password: f0836a4a8e345e00
  2020-04-22 20:37:01 [scrapy.middleware] INFO: Enabled extensions:
  ['scrapy.extensions.corestats.CoreStats',
  'scrapy.extensions.telnet.TelnetConsole',
  'scrapy.extensions.logstats.LogStats']
  2020-04-22 20:37:01 [scrapy.middleware] INFO: Enabled downloader middlewares:
  ['scrapy.downloadermiddlewares.httpauth.HttpAuthMiddleware',
   'scrapy.downloadermiddlewares.downloadtimeout.DownloadTimeoutMiddleware',
   'scrapy.downloadermiddlewares.defaultheaders.DefaultHeadersMiddleware',
   'scrapy.downloadermiddlewares.useragent.UserAgentMiddleware',
   'scrapy.downloadermiddlewares.retry.RetryMiddleware',
   'scrapy.downloadermiddlewares.redirect.MetaRefreshMiddleware',
   'scrapy.downloadermiddlewares.httpcompression.HttpCompressionMiddleware',
   'scrapy.downloadermiddlewares.redirect.RedirectMiddleware',
   'scrapy.downloadermiddlewares.cookies.CookiesMiddleware',
   'scrapy.downloadermiddlewares.httpproxy.HttpProxyMiddleware',
   'scrapy.downloadermiddlewares.stats.DownloaderStats']
  2020-04-22 20:37:01 [scrapy.middleware] INFO: Enabled spider middlewares:
  ['scrapy.spidermiddlewares.httperror.HttpErrorMiddleware',
   'scrapy.spidermiddlewares.offsite.OffsiteMiddleware',
   'scrapy.spidermiddlewares.referer.RefererMiddleware',
   'scrapy.spidermiddlewares.urllength.UrlLengthMiddleware',
   'scrapy.spidermiddlewares.depth.DepthMiddleware']
  2020-04-22 20:37:01 [scrapy.middleware] INFO: Enabled item pipelines:
  ['verbos.pipelines.MercadoPipeline']
  2020-04-22 20:37:01 [scrapy.core.engine] INFO: Spider opened
  2020-04-22 20:37:01 [scrapy.extensions.logstats] INFO: Crawled 0 pages (at 0 pages/min), scraped 0 items (at 0 items/min)
  2020-04-22 20:37:01 [scrapy.extensions.telnet] INFO: Telnet console listening on 127.0.0.1:6023
  2020-04-22 20:37:02 [scrapy.core.engine] DEBUG: Crawled (200) <GET https://pt.bab.la/verbo/portugues/ser> (referer: None)
  2020-04-22 20:37:03 [scrapy.core.scraper] ERROR: Spider error processing <GET https://pt.bab.la/verbo/portugues/ser> (referer: None)
  Traceback (most recent call last):
    File "c:\users\rodro\appdata\local\programs\python\python37-32\lib\site-packages\twisted\internet\defer.py", line 654, in _runCallbacks
      current.result = callback(current.result, *args, **kw)
    File "c:\users\rodro\appdata\local\programs\python\python37-32\lib\site-packages\scrapy\spiders\__init__.py", line 84, in parse
      raise NotImplementedError('{}.parse callback is not defined'.format(self.__class__.__name__))
  NotImplementedError: MercadoSpider.parse callback is not defined
  2020-04-22 20:37:03 [scrapy.core.engine] INFO: Closing spider (finished)
  2020-04-22 20:37:03 [scrapy.statscollectors] INFO: Dumping Scrapy stats:
  {'downloader/request_bytes': 228,
   'downloader/request_count': 1,
   'downloader/request_method_count/GET': 1,
   'downloader/response_bytes': 11949,
   'downloader/response_count': 1,
   'downloader/response_status_count/200': 1,
   'elapsed_time_seconds': 1.221998,
   'finish_reason': 'finished',
   'finish_time': datetime.datetime(2020, 4, 22, 23, 37, 3, 206234),
   'log_count/DEBUG': 1,
   'log_count/ERROR': 1,
   'log_count/INFO': 10,
   'response_received_count': 1,
   'scheduler/dequeued': 1,
   'scheduler/dequeued/memory': 1,
   'scheduler/enqueued': 1,
   'scheduler/enqueued/memory': 1,
   'spider_exceptions/NotImplementedError': 1,
   'start_time': datetime.datetime(2020, 4, 22, 23, 37, 1, 984236)}
  2020-04-22 20:37:03 [scrapy.core.engine] INFO: Spider closed (finished)

This is the error more clean:

NotImplementedError('{}.parse callback is not defined'.format(self.class.name)) NotImplementedError: MercadoSpider.parse callback is not defined

Thanks!