code: def test_gcf():
      fig = plt.figure("a label")
      buf = BytesIO()
      pickle.dump(fig, buf, pickle.HIGHEST_PROTOCOL)
      plt.close("all")
      assert (
          plt._pylab_helpers.Gcf.figs == {}
      )  # No figures must be left.
      fig = pickle.loads(buf.getbuffer())
      assert (
          plt._pylab_helpers.Gcf.figs != {}
      )  # A manager is there again.
      assert fig.get_label() == "a label"
  
imports: from io import BytesIO
  import ast
  import pickle
  import pickletools
  import numpy
  import pytest
  import matplotlib
  from matplotlib import cm
  from matplotlib.testing import subprocess_run_helper
  from matplotlib.testing.decorators import check_figures_equal
  from matplotlib.dates import rrulewrapper
  from matplotlib.lines import VertexSelector
  import matplotlib.pyplot
  import matplotlib.transforms
  import matplotlib.figure
  from mpl_toolkits.axes_grid1 import parasite_axes
label_desc: Use image node_id 6 for calling a global function with example usage: test_gcf() without return types