SVG - flash object by using opacity

i'm trying to do the same thing.
I'm inside the dynamic SVG

I would like so flash the object by using the opacity

somehow I feel that the property part is not necessary:
if you lok the debbugger, the item.Properties somehow returns this

If i don't use the property, I got an error.
I tried also with the visibility property

if i use this syntax, however, it works

is there any way to se the flashing inside the object itself?

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Split from SVG - PropertyFlashing() functionality.