code: def test_empty_tape():
      """Edge case where the tape is empty. Use this to test return types."""
  
      fig, ax = tape_mpl(QuantumScript())
  
      assert isinstance(fig, mpl.figure.Figure)
      assert isinstance(ax, mpl.axes._axes.Axes)
  
      assert fig.axes == [ax]
      plt.close()
  
imports: import pytest
  import pennylane
  from pennylane.drawer import tape_mpl
  from pennylane.tape import QuantumScript
label_desc: Use image node_id 1 for calling a global function with example usage: test_empty_tape() without return types