code: def extract_mail(issues):
      
      contacts = set()
      for idx, issue in enumerate(issues):
          printmp('Fetching issue #%s' % idx)
          for comment in issue.comments():
              comm = comment.as_dict()
              emails = list(email[0] for email in re.findall(MAIL_REGEX, comm['body'])
                  if not email[0].startswith('//') and not email[0].endswith('github.com') and
                  '@' in email[0])
              contacts |= set(emails)
      return contacts
docs: Extract mails that sometimes leak from issue comments.