class_docstr: Class to test cell picking.
class_docstr_tok: ["Class","to","test","cell","picking","."]
code: def __init__(self, mesh, cell_id, event_pos):
      self.mesh = mesh
      self.cell_id = cell_id
      self.point_id = None
      self.event_pos = event_pos
  
imports: import os
  from contextlib import nullcontext
  from pathlib import Path
  import numpy
  import pytest
  from numpy.testing import assert_allclose
  import mne
  from mne._fiff.constants import FIFF
  from mne.channels import DigMontage
  from mne.coreg import Coregistration
  from mne.datasets import testing
  from mne.io import read_info
  from mne.io.kit.tests import data_dir
  from mne.utils import catch_logging, get_config
  from mne.viz import _3d
label_desc: Use image node_id 1 to create a new TstVTKPicker object  with example: obj = TstVTKPicker(mesh, cell_id, event_pos)