def populate_obj(self, obj, keys=None):
        """Given the `obj` populate it using self.store items."""
        keys = keys or self.keys()
        for key in keys:
            key = key.upper()
            value = self.get(key, empty)
            if value is not empty:
                setattr(obj, key, value)
Given the `obj` populate it using self.store items.