code: def test_missing_back_button():
      import matplotlib.pyplot as plt
      from matplotlib.backends.backend_tkagg import NavigationToolbar2Tk
  
      class Toolbar(NavigationToolbar2Tk):
          # Only display the buttons we need.
          toolitems = [
              t
              for t in NavigationToolbar2Tk.toolitems
              if t[0] in ("Home", "Pan", "Zoom")
          ]
  
      fig = plt.figure()
      print("success")
      Toolbar(
          fig.canvas, fig.canvas.manager.window
      )  # This should not raise.
      print("success")
  
file_path: matplotlib/lib/matplotlib/tests/test_backend_tk.py
imports: import functools
  import importlib
  import os
  import platform
  import subprocess
  import sys
  import pytest
  from matplotlib import _c_internal_utils
  from matplotlib.testing import subprocess_run_helper
label_desc: Use image node_id 6 for calling a global function with example usage: test_missing_back_button() without return types