code: def test_mark_area_options_remove_none():
      label_opts = LabelOpts()
      option = MarkAreaOpts(label_opts=label_opts)
      expected = {
          "silent": False,
          "label": label_opts,
      }
      assert_equal(expected, remove_key_with_none_value(option.opts))
  
file_path: pyecharts/test/test_series_options.py
imports: from nose.tools import assert_equal
  from pyecharts.commons.utils import remove_key_with_none_value
  from pyecharts.options.series_options import LabelOpts, ItemStyleOpts, MarkPointItem, MarkLineItem, MarkAreaItem, MarkAreaOpts, MinorTickOpts, MinorSplitLineOpts, TreeMapBreadcrumbOpts
label_desc: Use image node_id 6 for calling a global function with example usage: test_mark_area_options_remove_none() without return types