code: def test_empty_marginal__get_marginal_layers():
      marginals = _get_marginal_layers(
          **_get_marginal_layers_props(marginal="")
      )
      assert 0 == len(marginals)
  
file_path: lets-plot/python-package/test/plot/test_bistro_common.py
imports: import pytest
  from lets_plot.bistro._plot2d_common import _get_bin_params_2d, _get_geom2d_layer, _get_marginal_layers
label_desc: Use image node_id 10 for calling a global function with example usage: test_empty_marginal__get_marginal_layers() without return types