docs: def get_collaborators(self, affiliation=github.GithubObject.NotSet):
          """
          :calls: `GET /repos/:owner/:repo/collaborators <http://developer.github.com/v3/repos/collaborators>`_
          :param affiliation: string
          :rtype: :class:`github.PaginatedList.PaginatedList` of :class:`github.NamedUser.NamedUser`
          """
  
          url_parameters = dict()
          allowed_affiliations = ['outside', 'direct', 'all']
          if affiliation is not github.GithubObject.NotSet:
              assert isinstance(affiliation, str), affiliation
              assert affiliation in allowed_affiliations, \
                  'Affiliation can be one of ' + ', '.join(allowed_affiliations)
              url_parameters['affiliation'] = affiliation
  
          return github.PaginatedList.PaginatedList(
              github.NamedUser.NamedUser,
              self._requester,
              self.url + "/collaborators",
              url_parameters
          )