[Matplotlib-users] wxmpl: Can't create printer "PDF" because the id "PDF" is already used

I just created a small wxmpl example that I really like (attached),
but when I run it, I get these error messages:

** (python:18091): WARNING **: Can't create printer "PDF" because the
id "PDF" is already used

(python:18091): GnomePrintCupsPlugin-WARNING **: The CUPS printer PDF
could not be created


(python:18091): GnomePrintCupsPlugin-WARNING **: The data for the CUPS
printer PDF could not be loaded.


I don't know if this is wxmpl specific, caused by wxPython, or caused
by matplotlib, but I would like to make it go away.  Any thoughts?

Thanks,

Ryan