code: def test_trame_jupyter_custom_handler():
      def handler(viewer, src, **kwargs):
          return IFrame(src, "75%", "500px")
  
      plotter = pv.Plotter(notebook=True)
      _ = plotter.add_mesh(pv.Cone())
      iframe = plotter.show(
          jupyter_backend="trame",
          jupyter_kwargs=dict(handler=handler),
          return_viewer=True,
      )
      assert isinstance(iframe, IFrame)
  
imports: import os
  from IPython.display import IFrame
  import numpy
  import pytest
  import pyvista
  from pyvista import examples
label_desc: Use image node_id 11 for calling a global function with example usage: test_trame_jupyter_custom_handler() and returns: IFrame