What am I doing wrong with my pydo.Field class?

I've defined a class derived from pydo.Field as follows:

    class XMLPara(pydo.Field):

        def __get__(self, obj, type_):
            """descriptor method"""
            if obj is None:
                return None
            return tidy(obj[self.name])

I then use it in my schema as follows:

    class Researcher(ResExpTable):
        fields = (
            pydo.Unique('USERNAME'),
            XMLPara('RES_EXP'),
            ....

However a print statement in XMLPara.__get__ indicates that 'obj' is
always None. Am I defining and using XMLPara correctly?


Hamish


-------------------------------------------------------
This SF.Net email is sponsored by:
Power Architecture Resource Center: Free content, downloads, discussions,
and more. http://solutions.newsforge.com/ibmarch.tmpl