code: def test_chart_append_color(fake_writer):
      x_data = ["周一", "周二", "周三", "周四", "周五", "周六", "周日"]
      y_data1 = [140, 232, 101, 264, 90, 340, 250]
      y_data2 = [120, 282, 111, 234, 220, 340, 310]
  
      c = (
          Line()
          .add_xaxis(xaxis_data=x_data)
          .add_yaxis(
              series_name="品类 1", y_axis=y_data1, color="#80FFA5"
          )
          .add_yaxis(
              series_name="品类 2", y_axis=y_data2, color="#00DDFF"
          )
      )
      c.render()
      _, content = fake_writer.call_args[0]
      # Old Version (Before 2.0)
      # default_colors = (
      #     "#c23531 #2f4554 #61a0a8 #d48265 #749f83 #ca8622 #bda29a #6e7074 "
      #     "#546570 #c4ccd3 #f05b72 #ef5b9c #f47920 #905a3d #fab27b #2a5caa "
      #     "#444693 #726930 #b2d235 #6d8346 #ac6767 #1d953f #6950a1 #918597"
      # ).split()
  
      # New Version
      default_colors = (
          "#5470c6 #91cc75 #fac858 #ee6666 #73c0de #3ba272 #fc8452 #9a60b4 "
          "#ea7ccc"
      ).split()
      expected_result = ["#80FFA5", "#00DDFF", *default_colors]
      assert_equal(c.colors, expected_result)
  
file_path: pyecharts/test/test_chart.py
imports: from unittest.mock import patch
  from nose.tools import assert_equal, assert_in
  from pyecharts import options
  from pyecharts.charts import Line, Bar
label_desc: Use image node_id 11 for calling a global function with example usage: test_chart_append_color(fake_writer) without return types