code: def test_geo_flow_gl(fake_writer):
      c = (
          Geo()
          .add_schema(maptype="china")
          .add(
              "geo",
              [list(z) for z in zip(Faker.provinces, Faker.values())],
              type_=ChartType.FLOWGL,
          )
          .set_series_opts(label_opts=opts.LabelOpts(is_show=False))
          .set_global_opts(visualmap_opts=opts.VisualMapOpts())
      )
      assert_equal(c.theme, "white")
      c.render()
      _, content = fake_writer.call_args[0]
      assert_in("canvas", content)
  
imports: from unittest.mock import patch
  from nose.tools import assert_equal, assert_in
  from pyecharts import options
  from pyecharts.charts import Geo
  from pyecharts.faker import Faker
  from pyecharts.globals import ChartType, SymbolType
label_desc: Use image node_id 14 for calling a global function with example usage: test_geo_flow_gl(fake_writer) without return types