I'd like to get checksum of a cell view layout. Is there a built-in function in Cadence to do this?

I'd like to get SHA hash (checksum) of a cell view layout. Is there a built-in function in Cadence to do this? Long explanation: What I need is a way to compare two layouts in a very compute and time efficient manner. If I had a SHA256 hash that compressed all the shapes, text, properties, etc... of a layout I could use the SHA hash key to compare layouts. This could tell me if a layout view changed over time (it won't tell what changed - just THAT it changed). The cell view layout is in the end just an object... so this seems doable by extracting key fields of the layout object and sending the data through a SHA algorithm. Any help/clues are appreciated. ps: no it doesn't have to be SHA hash, anything close would work too. -AC