class_docstr: A mock Comm object.
  
  Can be used to inspect calls to Comm's open/send/close methods.
code: def __init__(self, *args, **kwargs):
      self.log_open = []
      self.log_send = []
      self.log_close = []
      super(MockComm, self).__init__(*args, **kwargs)
  
file_path: vegafusion/python/vegafusion-jupyter/tests/conftest.py
imports: import pytest
  from ipykernel.comm import Comm
  from ipywidgets import Widget
label_desc: Use image node_id 1 to create a new MockComm object from inherited base classes: Comm with example: obj = MockComm()