Ensure that printed mappings are YAML friendly.

def finalizer(self, data):
        '''
        Ensure that printed mappings are YAML friendly.
        '''
        def explore(data):
            if isinstance(data, (dict, OrderedDict)):
                return PrintableDict(
                    [(key, explore(value)) for key, value in six.iteritems(data)]
                )
            elif isinstance(data, (list, tuple, set)):
                return data.__class__([explore(value) for value in data])
            return data
        return explore(data)