Example for Page and Document

[inkyusa]

Hi,
Thank you for contributing/maintaining a nice package.
I'm just wondering that if I want to set a canvas with width = 1000mm and height = 800mm with 20mm margin for all surrounding sides (i.e., top, left, right, and bottom have 20mm white space), is there any similar example to do this?
I found Page APIs from https://pyx-project.org/manual/document.html but it is a bit difficult to follow for a new pyx user.
Thanks again!.
Best regards