How do I catch a 404 error in urllib? (python 3)

I've been reading tens of examples for similar issues, but I can't get any of the solutions I've seen or their variants to run. I'm screen scraping, and I just want to ignore 404 errors (skip the pages). I get 'AttributeError: 'module' object has no attribute 'HTTPError'. I've tried 'URLError' as well. I've seen the near identical syntax accepted as working answers. Any ideas? Here's what I've got: ``` import urllib import datetime from bs4 import BeautifulSoup class EarningsAnnouncement: def __init__(self, Company, Ticker, EPSEst, AnnouncementDate, AnnouncementTime): self.Company = Company self.Ticker = Ticker self.EPSEst = EPSEst self.AnnouncementDate = AnnouncementDate self.AnnouncementTime = AnnouncementTime webBaseStr = 'http://biz.yahoo.com/research/earncal/' earningsAnnouncements = [] dayVar = datetime.date.today() for dte in range(1, 30): currDay = str(dayVar.day) currMonth = str(dayVar.month) currYear = str(dayVar.year) if (len(currDay)==1): currDay = '0' + currDay if (len(currMonth)==1): currMonth = '0' + currMonth dateStr = currYear + currMonth + currDay webString = webBaseStr + dateStr + '.html' try: #with urllib.request.urlopen(webString) as url: page = url.read() page = urllib.request.urlopen(webString).read() soup = BeautifulSoup(page) tbls = soup.findAll('table') tbl6= tbls[6] rows = tbl6.findAll('tr') rows = rows[2:len(rows)-1] for earn in rows: earningsAnnouncements.append(EarningsAnnouncement(earn.contents[0], earn.contents[1], earn.contents[3], dateStr, earn.contents[3])) except urllib.HTTPError as err: if err.code == 404: continue else: raise dayVar += datetime.timedelta(days=1) ```