code: def add_toolitem(
      self, name, group, position, image_file, description, toggle
  ):
      if toggle:
          button = Gtk.ToggleButton()
      else:
          button = Gtk.Button()
      button.set_label(name)
      button.add_css_class("flat")
  
      if image_file is not None:
          image = Gtk.Image.new_from_gicon(
              Gio.Icon.new_for_string(image_file)
          )
          button.set_child(image)
          button.add_css_class("image-button")
  
      if position is None:
          position = -1
  
      self._add_button(button, group, position)
      signal = button.connect("clicked", self._call_tool, name)
      button.set_tooltip_text(description)
      self._toolitems.setdefault(name, [])
      self._toolitems[name].append((button, signal))
  
imports: import functools
  import io
  import os
  import matplotlib
  from matplotlib import _api, backend_tools, cbook
  from matplotlib.backend_bases import ToolContainerBase, KeyEvent, LocationEvent, MouseEvent, ResizeEvent, CloseEvent
  from gi.repository import Gio, GLib, Gtk, Gdk, GdkPixbuf
  from .None import _backend_gtk
  from ._backend_gtk import _BackendGTK, _FigureCanvasGTK, _FigureManagerGTK, _NavigationToolbar2GTK, TimerGTK
label_desc: Use image node_id 2 for calling the ToolbarGTK4 obj's underlying member method code with example usage: obj.add_toolitem(name, group, position, image_file, description, toggle) without return types