code: def test_grab_clear():
      fig, ax = plt.subplots()
  
      fig.canvas.grab_mouse(ax)
      assert fig.canvas.mouse_grabber == ax
  
      fig.clear()
      assert fig.canvas.mouse_grabber is None
  
imports: import re
  from matplotlib import path, transforms
  from matplotlib.backend_bases import FigureCanvasBase, KeyEvent, LocationEvent, MouseButton, MouseEvent, NavigationToolbar2, RendererBase
  from matplotlib.backend_tools import RubberbandBase
  from matplotlib.figure import Figure
  from matplotlib.testing._markers import needs_pgf_xelatex
  import matplotlib.pyplot
  import numpy
  import pytest
label_desc: Use image node_id 6 for calling a global function with example usage: test_grab_clear() without return types