Programmatically update parameter value does not update widget

[suyang-nju]

See the following code. xystream.event(y=-0.3) updates y value to -0.3, but the slider widget is not updated accordingly.

from holoviews.streams import Stream
import param
import paramnb

class XY(Stream):
    x = param.Number(default=0.0, bounds=(-0.5, 0.5))
    y = param.Number(default=0.0, bounds=(-0.5, 0.5))

    def event(self, **kwargs):
        super(XY, self).event(**kwargs)
        print(self.contents)

xystream = XY()
paramnb.Widgets(xystream, callback=xystream.event, on_init=True)

# does not update y slider
xystream.event(y=-0.3) 

[suyang-nju]

Solved by doing

w = paramnb.Widgets.instance()
w(xystream, callback=xystream.event, on_init=True)
w.widget('y').value = xystream.contents['y']

Not sure if this is the right way to do it?