code: def iter_all_users(self, number=-1, etag=None, per_page=None):
          
          url = self._build_url('users')
          return self._iter(int(number), url, User,
                            params={'per_page': per_page}, etag=etag)
docs: Iterate over every user in the order they signed up for GitHub.
  
          :param int number: (optional), number of users to return. Default: -1,
              returns all of them
          :param str etag: (optional), ETag from a previous request to the same
              endpoint
          :param int per_page: (optional), number of users to list per request
          :returns: generator of :class:`User <github3.users.User>`