How does echarts switch themes

One-line summary [problem brief]
how to switch between topics, is there any way?

Version & Environment [version and environment]
ECharts version [ECharts version]: 4.1.0
Browser version [browser type and version]: Google 67.0.3396.87 (official version)
OS Version [operating system type and version]: Microsoft win 10

Expected behaviour [expected result]
switch topics by method

I can pass in themes when I find init, but how to switch themes after initialization

you can see

in http://gallery.echartsjs.com/..

you can click directly to switch topics, but there is no relevant method found in the document

is there any other documentation related to echarts topic configuration?

Canvas data-visualization css javascript echarts

Mar.20,2021

var chart = echarts.init (dom, 'light'); / / when the table is initialized, it is switched to the light theme

in fact, you can know what to do by looking at the document.

http://echarts.baidu.com/tuto.

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