class_docstr: Send client id and role to server
  
  Parameters
  ----------
  client_id : int
      ID of client
  role : str
      role of client
class_docstr_tok: ["Send","client","id","and","role","to","server","Parameters","--","--","--","--","--","client_id",":","int","ID","of","client","role",":","str","role","of","client"]
code: def process_request(self, server_state):
      kv_store = server_state.kv_store
      role = server_state.roles.setdefault(self.group_id, {})
      if self.role not in role:
          role[self.role] = set()
          if kv_store is not None:
              barrier_count = kv_store.barrier_count.setdefault(
                  self.group_id, {}
              )
              barrier_count[self.role] = 0
      role[self.role].add((self.client_id, self.machine_id))
      total_count = 0
      for key in role:
          total_count += len(role[key])
      # Clients are blocked util all clients register their roles.
      if total_count == rpc.get_num_client():
          res_list = []
          for target_id in range(rpc.get_num_client()):
              res_list.append(
                  (target_id, RegisterRoleResponse(REG_ROLE_MSG))
              )
          return res_list
      return None
  
imports: import os
  import numpy
  from .None import rpc
label_desc: Use image node_id 4 for calling the RegisterRoleRequest obj's underlying member method code with example usage: obj.process_request(server_state) and returns: None, res_list