code: def updateGroupResponse(self, group, vendorSpecific=None):
          
          mmp_dict = {'group': ('group.xml', group.toxml('utf-8'))}
          return self.PUT('groups', fields=mmp_dict, headers=vendorSpecific)
docs: CNIdentity.addGroupMembers(session, groupName, members) → boolean
          https://releases.dataone.org/online/api-
          documentation-v2.0.1/apis/CN_APIs.html#CNIdentity.addGroupMembers.
  
          Args:
            group:
            vendorSpecific:
  
          Returns: