Returns dict of current values for all tracked fields

def current(self, fields=None):
        """Returns dict of current values for all tracked fields"""
        if fields is None:
            deferred_fields = self.deferred_fields
            if deferred_fields:
                fields = [
                    field for field in self.fields
                    if field not in deferred_fields
                ]
            else:
                fields = self.fields

        return dict((f, self.get_field_value(f)) for f in fields)