class_docstr: A client class
  
  Provide the connection tool functions for ClientProvider.
docstr: Connect to server.
code: def connect_server(self):
      """Connect to server."""
      try:
          self.sio.connect(
              "ws://" + self.server_host + ":" + str(self.server_port)
          )
      except socketio.exceptions.ConnectionError:
          self.logger.error(
              "Cannot connect to server - check your network or server status"
          )
  
file_path: qlib/qlib/data/client.py
imports: from __future__ import division
  from __future__ import print_function
  import socketio
  import qlib
  from ..config import C
  from ..log import get_module_logger
  import pickle
label_desc: Use image node_id 2 for calling the Client obj's underlying member method code with example usage: obj.connect_server() without return types