How to enable sand dupe in papermc or plugin code example

Example: How to enable sand dupe in papermc or plugin

yes, there is a way to enable duping on paper. It is located in the paper.yml 
file. First stop the server. Make sure its online. In the file find where 
it says allow-piston-duplication: false". Set that option to true. 
Click save and start the server again. Think that is the right option that 
enables duping.