'Get a possibly inherited attribute specified by name
of a schema element specified by nameoroid.
Returns None if class attribute is not set at all.
Raises KeyError if no schema element is found by nameoroid.'

def get_inheritedattr(self, se_class, nameoroid, name):

    se = self.sed[se_class][self.getoid(se_class, nameoroid)]
    try:
        result = getattr(se, name)
    except AttributeError:
        result = None
    if ((result is None) and se.sup):
        result = self.get_inheritedattr(se_class, se.sup[0], name)
    return result
