在pyyaml中，SafeLoader不包含python本机类型的加载程序，仅包含yaml规范中定义的类型。你可以看到类型的
SafeLoader和
Loader这里下面的互动样本。
您可以定义一个新的Loader类，该类添加了python元组，但未添加其他类型，因此它仍然非常安全：
import yamlclass PrettySafeLoader(yaml.SafeLoader): def construct_python_tuple(self, node): return tuple(self.construct_sequence(node))PrettySafeLoader.add_constructor( u'tag:yaml.org,2002:python/tuple', PrettySafeLoader.construct_python_tuple)doc = yaml.dump(tuple("foo bar baaz".split()))print repr(doc)thing = yaml.load(doc, Loader=PrettySafeLoader)print thing导致：
'!!python/tuple [foo, bar, baaz]n'('foo', 'bar', 'baaz')请参阅下面的与SafeLoader和Loader类关联的构造函数。
>>> yaml.SafeLoader.yaml_constructors{None: <unbound method SafeConstructor.construct_undefined>, u'tag:yaml.org,2002:binary': <unbound method SafeConstructor.construct_yaml_binary>, u'tag:yaml.org,2002:bool': <unbound method SafeConstructor.construct_yaml_bool>, u'tag:yaml.org,2002:float': <unbound method SafeConstructor.construct_yaml_float>, u'tag:yaml.org,2002:int': <unbound method SafeConstructor.construct_yaml_int>, u'tag:yaml.org,2002:map': <unbound method SafeConstructor.construct_yaml_map>, u'tag:yaml.org,2002:null': <unbound method SafeConstructor.construct_yaml_null>, u'tag:yaml.org,2002:omap': <unbound method SafeConstructor.construct_yaml_omap>, u'tag:yaml.org,2002:pairs': <unbound method SafeConstructor.construct_yaml_pairs>, u'tag:yaml.org,2002:seq': <unbound method SafeConstructor.construct_yaml_seq>, u'tag:yaml.org,2002:set': <unbound method SafeConstructor.construct_yaml_set>, u'tag:yaml.org,2002:str': <unbound method SafeConstructor.construct_yaml_str>, u'tag:yaml.org,2002:timestamp': <unbound method SafeConstructor.construct_yaml_timestamp>}>>> yaml.Loader.yaml_constructors{None: <unbound method SafeConstructor.construct_undefined>, u'tag:yaml.org,2002:binary': <unbound method SafeConstructor.construct_yaml_binary>, u'tag:yaml.org,2002:bool': <unbound method SafeConstructor.construct_yaml_bool>, u'tag:yaml.org,2002:float': <unbound method SafeConstructor.construct_yaml_float>, u'tag:yaml.org,2002:int': <unbound method SafeConstructor.construct_yaml_int>, u'tag:yaml.org,2002:map': <unbound method SafeConstructor.construct_yaml_map>, u'tag:yaml.org,2002:null': <unbound method SafeConstructor.construct_yaml_null>, u'tag:yaml.org,2002:omap': <unbound method SafeConstructor.construct_yaml_omap>, u'tag:yaml.org,2002:pairs': <unbound method SafeConstructor.construct_yaml_pairs>, u'tag:yaml.org,2002:python/bool': <unbound method Constructor.construct_yaml_bool>, u'tag:yaml.org,2002:python/complex': <unbound method Constructor.construct_python_complex>, u'tag:yaml.org,2002:python/dict': <unbound method Constructor.construct_yaml_map>, u'tag:yaml.org,2002:python/float': <unbound method Constructor.construct_yaml_float>, u'tag:yaml.org,2002:python/int': <unbound method Constructor.construct_yaml_int>, u'tag:yaml.org,2002:python/list': <unbound method Constructor.construct_yaml_seq>, u'tag:yaml.org,2002:python/long': <unbound method Constructor.construct_python_long>, u'tag:yaml.org,2002:python/none': <unbound method Constructor.construct_yaml_null>, u'tag:yaml.org,2002:python/str': <unbound method Constructor.construct_python_str>, u'tag:yaml.org,2002:python/tuple': <unbound method Constructor.construct_python_tuple>, u'tag:yaml.org,2002:python/unipre': <unbound method Constructor.construct_python_unipre>, u'tag:yaml.org,2002:seq': <unbound method SafeConstructor.construct_yaml_seq>, u'tag:yaml.org,2002:set': <unbound method SafeConstructor.construct_yaml_set>, u'tag:yaml.org,2002:str': <unbound method SafeConstructor.construct_yaml_str>, u'tag:yaml.org,2002:timestamp': <unbound method SafeConstructor.construct_yaml_timestamp>}
