code: def add_members(self, project, params={}, **options): 
          
          path = "/projects/%s/addMembers" % (project)
          return self.client.post(path, params, **options)
docs: Adds the specified list of users as members of the project. Returns the updated project record.
  
          Parameters
          ----------
          project : {Id} The project to add members to.
          [data] : {Object} Data for the request
            - members : {Array} An array of members to add to the project.