Perspective how to turn an arrow icon and change a container size slower?

Ignition
1

I remember I had a handy technique to click on a flex container that:
Turned an arrow icon
Displayed a flex container under it

I think that changing the size of the container was part of the trick that made it kind of animate rather than just appear.
My current script:

	if self.custom.show :
		self.getChild("Icon").props.path='material/keyboard_arrow_right'
		self.getSibling("flexReports").position.basis = '0px'
		self.custom.show= 0
	else:
		self.getChild("Icon").props.path='material/keyboard_arrow_down'
		self.getSibling("flexReports").position.basis = '500px'
		self.custom.show = 1

Can't seem to find the thread where I learned how to perform the transition slower though.