Echart pane doesn't fully work with pyechart

[jbogaardt]

Echart pane doesn't behave correctly when wrapping a pyechart object + interacting wigh widgets. Refer to this discourse discussion.

Description of expected behavior and the observed behavior

I expect this to work, and it initializes, but upon update it returns an error.

from pyecharts.charts import Bar
import panel as pn
pn.extension('echarts')


bar1 = pn.widgets.IntSlider(start=1, end=100, value=50)
bar2 = pn.widgets.IntSlider(start=1, end=100, value=50)

@pn.depends(bar1.param.value, bar2.param.value)
def plot(bar1, bar2):
    my_plot= (Bar()
        .add_xaxis(['Bar1', 'Bar2'])
        .add_yaxis('Values', [bar1, bar2])
    )
    return pn.pane.ECharts(my_plot, width=500, height=250)
pn.Row(pn.Column(bar1, bar2), plot)

Stack traceback and/or browser JavaScript console output

ValueError: expected an element of Dict(String, Any), got <pyecharts.charts.basic_charts.bar.Bar object at 0x7ffada0b5910>