code: def test_pie_item_base(fake_writer):
      d = [
          opts.PieItem(name="河马", value=131),
          opts.PieItem(name="蟒蛇", value=89),
          opts.PieItem(name="老虎", value=149),
          opts.PieItem(name="大象", value=178),
      ]
      c = (
          Pie()
          .add("", d)
          .set_series_opts(
              label_opts=opts.LabelOpts(formatter="{b}: {c}")
          )
      )
      c.render()
      _, content = fake_writer.call_args[0]
      assert_equal(c.theme, "white")
      assert_equal(c.renderer, "canvas")
  
imports: from unittest.mock import patch
  from nose.tools import assert_equal, assert_in
  from pyecharts import options
  from pyecharts.charts import Pie
  from pyecharts.faker import Faker
label_desc: Use image node_id 2 for calling a global function with example usage: test_pie_item_base(fake_writer) without return types