OnMouseOver Event - Perspective

I want to change visibility of a markdown when my mouse is over a label. I use onMouseOver and onMouseLeave where I use scripting to change the visibility value. That’s my code:

self.getSibling("I2603264LZR_popup").meta.visible = "True"
self.getSibling("I2603264LZR_popup").meta.visible = "False"

When my mouse is over my label, nothing happens, I don’t understand why.

Thanks for your help!

it should not be a string but a boolean

self.getSibling("I2603264LZR_popup").meta.visible = True
... = False