Who said "You can't teach an old dog new tricks."?

This quote is attributed to Poppie.

You can't teach an old dog new tricks. - Poppie

"You can't teach an old dog new tricks."

Poppie Philosophy

"These pretzels are making me thirsty."

"Master of your domain? That's what it's all about."

"Giddy-up!"

"Not that there's anything wrong with that."

"I've seen the worst humanity has to offer."

"Sometimes I wonder if the world is worth saving."

"Every choice shapes our destiny."

"Order is the foundation of a good life."