code: def _gen_bar_chart(fake_writer) -> str:
      c = (
          Bar()
          .add_xaxis(["A", "B", "C"])
          .add_yaxis("series0", [1, 2, 4])
          .add_yaxis("series1", [2, 3, 6])
      )
      c.render()
      filename, _ = fake_writer.call_args[0]
      return filename
  
file_path: pyecharts/test/test_snapshot.py
imports: import os
  from unittest.mock import patch
  from nose.tools import assert_equal, raises
  from pyecharts.charts import Bar
  from pyecharts.render import make_snapshot
  from pyecharts.render.snapshot import save_as, save_as_png, save_as_text, decode_base64
label_desc: Use image node_id 6 for calling a global function with example usage: _gen_bar_chart(fake_writer) and returns: filename