code: def _init_browser_backend():
      global MNE_BROWSER_BACKEND
  
      # check if MNE_BROWSER_BACKEND is not None and valid or get it from config
      loaded_backend = MNE_BROWSER_BACKEND or get_config(
          key="MNE_BROWSER_BACKEND", default=None
      )
      if loaded_backend is not None:
          set_browser_backend(loaded_backend)
          return MNE_BROWSER_BACKEND
      else:
          errors = dict()
          # Try import of valid browser backends
          for name in VALID_BROWSE_BACKENDS:
              try:
                  _load_backend(name)
              except ImportError as exc:
                  errors[name] = str(exc)
              else:
                  MNE_BROWSER_BACKEND = name
                  break
          else:
              raise RuntimeError(
                  "Could not load any valid 2D backend:\n"
                  + "\n".join(
                      f"{key}: {val}" for key, val in errors.items()
                  )
              )
  
          return MNE_BROWSER_BACKEND
  
imports: import importlib
  from abc import ABC, abstractmethod
  from collections import OrderedDict
  from contextlib import contextmanager
  from copy import deepcopy
  from itertools import cycle
  import numpy
  from .._fiff.pick import _DATA_CH_TYPES_SPLIT
  from ..defaults import _handle_default
  from ..filter import _iir_filter, _overlap_add_filter
  from ..fixes import _compare_version
  from ..utils import _check_option, _get_stim_channel, _validate_type, get_config, logger, set_config, verbose
  from .backends._utils import VALID_BROWSE_BACKENDS
  from .utils import _get_color_list, _setup_plot_projector, _show_browser
label_desc: Use image node_id 5 for calling a global function with example usage: _init_browser_backend() and returns: MNE_BROWSER_BACKEND, MNE_BROWSER_BACKEND