code: def _spawn_child_fig(fig, attr, browse_backend, key):
      # starting state
      n_figs = browse_backend._get_n_figs()
      n_children = len(fig.mne.child_figs)
      # spawn the child fig
      fig._fake_keypress(key)
      # make sure the figure was actually spawned
      assert len(fig.mne.child_figs) == n_children + 1
      assert browse_backend._get_n_figs() == n_figs + 1
      # make sure the parent fig knows the child fig's name
      child_fig = getattr(fig.mne, attr)
      assert child_fig is not None
      return child_fig
  
imports: import itertools
  import os
  from copy import deepcopy
  import matplotlib.pyplot
  import numpy
  import pytest
  from matplotlib import backend_bases
  from numpy.testing import assert_allclose
  from mne import Annotations, create_info, pick_types
  from mne._fiff.pick import _DATA_CH_TYPES_ORDER_DEFAULT, _PICK_TYPES_DATA_DICT
  from mne.annotations import _sync_onset
  from mne.datasets import testing
  from mne.io import RawArray
  from mne.utils import _assert_no_instances, _dt_to_stamp, _record_warnings, check_version, get_config, set_config
  from mne.viz import plot_raw, plot_sensors
  from mne.viz.utils import _fake_click, _fake_keypress
label_desc: Use image node_id 7 for calling a global function with example usage: _spawn_child_fig(fig, attr, browse_backend, key) and returns: child_fig