code: def issue(self, owner, repository, number):
          
          repo = self.repository(owner, repository)
          if repo:
              return repo.issue(number)
          return None
docs: Fetch issue #:number: from https://github.com/:owner:/:repository:
  
          :param str owner: (required), owner of the repository
          :param str repository: (required), name of the repository
          :param int number: (required), issue number
          :return: :class:`Issue <github3.issues.Issue>`