code: def test_manager_get_hosted_table_names_with_cmd(self):
      manager = PerspectiveManager()
      table = Table(data)
      manager.host_table("table1", table)
      message = {"id": 1, "cmd": "get_hosted_table_names"}
      post_callback = partial(
          self.validate_post,
          expected={"id": 1, "data": ["table1"]},
      )
      manager._process(message, post_callback)
  
imports: import json
  import time
  import numpy
  import pyarrow
  from datetime import datetime
  from functools import partial
  from pytest import raises
  from perspective import Table, PerspectiveError, PerspectiveManager
label_desc: Use image node_id 8 for calling the TestPerspectiveManager obj's underlying member method code with example usage: obj.test_manager_get_hosted_table_names_with_cmd() without return types