code: def issue_line_with_user(self, line, issue):
          
          if not issue.get("pull_request") or not self.options.author:
              return line
  
          if not issue.get("user"):
              line += u" (Null user)"
          elif self.options.username_as_tag:
              line += u" (@{0})".format(
                  issue["user"]["login"]
              )
          else:
              line += u" ([{0}]({1}))".format(
                  issue["user"]["login"], issue["user"]["html_url"]
              )
          return line
docs: If option author is enabled, a link to the profile of the author
          of the pull reqest will be added to the issue line.
  
          :param str line: String containing a markdown-formatted single issue.
          :param dict issue: Fetched issue from GitHub.
          :rtype: str
          :return: Issue line with added author link.