Erase all flash while uploading

I am trying to erase all fash on the upload button/command. The project is Tasmota in case that matters.
I was playing around with ‘upload_flags’. Either that is not right or I am not using it right.
I have tried upload = with both -e and --erase-all. I get the help screen and it says unrecognized arguments. Can it be done what I am trying? If so how?