def are_stringable_keys(self, m):
        """Test whether the keys within a map are stringable - a simple map,
        that can be optimized and whose keys can be cached
        """
        for x in m.keys():
            if len(self.handlers[x].tag(x)) != 1:
                return False
        return True
Test whether the keys within a map are stringable - a simple map,
        that can be optimized and whose keys can be cached