code: def update(self, users=None, groups=None):
          
  
          if users is not None and isinstance(users, string_types):
              users = (users,)
          if groups is not None and isinstance(groups, string_types):
              groups = (groups,)
  
          data = {
              'id': self.id,
              'categorisedActors': {
                  'atlassian-user-role-actor': users,
                  'atlassian-group-role-actor': groups}}
  
          super(Role, self).update(**data)
docs: Add the specified users or groups to this project role. One of ``users`` or ``groups`` must be specified.
  
          :param users: a user or users to add to the role
          :type users: string, list or tuple
          :param groups: a group or groups to add to the role
          :type groups: string, list or tuple