def matches_pattern(self, other):
        """Test if the current instance matches a template instance."""
        ismatch = False
        if isinstance(other, Userdata):
            for key in self._userdata:
                if self._userdata[key] is None or other[key] is None:
                    ismatch = True
                elif self._userdata[key] == other[key]:
                    ismatch = True
                else:
                    ismatch = False
                    break
        return ismatch