相关疑难解决方法(0)

我有以下XML,我想用Python解析ElementTree:

<rdf:RDF xml:base="http://dbpedia.org/ontology/"
    xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
    xmlns:owl="http://www.w3.org/2002/07/owl#"
    xmlns:xsd="http://www.w3.org/2001/XMLSchema#"
    xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"
    xmlns="http://dbpedia.org/ontology/">

    <owl:Class rdf:about="http://dbpedia.org/ontology/BasketballLeague">
        <rdfs:label xml:lang="en">basketball league</rdfs:label>
        <rdfs:comment xml:lang="en">
          a group of sports teams that compete against each other
          in Basketball
        </rdfs:comment>
    </owl:Class>

</rdf:RDF>

我想找到所有owl:Class标签,然后提取其中所有rdfs:label实例的值.我使用以下代码:

tree = ET.parse("filename")
root = tree.getroot()
root.findall('owl:Class')

由于命名空间,我收到以下错误.

SyntaxError: prefix 'owl' not found in prefix map

我尝试在http://effbot.org/zone/element-namespaces.htm上阅读该文档,但由于上述XML具有多个嵌套命名空间,因此我仍然无法正常工作.

请告诉我如何更改代码以查找所有owl:Class标签.