[AstroPy] Question about WCS distortion coefficients

[Brian York]

Greetings,

Given that I have the following data:
	- RA
	- DEC
	- PA
	- Plate Scale
I can create a distortion-free WCS using astropy. If I also have:
	- polynomial degree (2 or 3)
	- X and Y coefficients (X10,X11,X20,X21,X22,X30-X33 if degree is 3, same
for y)

How do I go about modifying that WCS to include the necessary distortion
information? Any assistance would be appreciated.

	-Brian York