Use Python to test whether a layer has a join or relate

I've used the "Add Join" and "Remove Join" tools via Python. I want my script to first test whether a layer has a join or not, and if it does, to remove it. This is because I've had problems when trying to make a second join on a field.

See http://help.arcgis.com/en/arcgisdesk...00000063000000

Is there a method in Python to return the join information for a particular field? Thanks