XML findall在第一个查找处停止

我试图用python2.7和xml.etree.ElementTree.

下面是我用来遍历XML的循环。

prefixes=['conn','dummy']
for datasource in root.findall('.//datasource'):
        for relation in datasource.findall('.//relation'):
            if 'connection' in relation.attrib:
                if relation.attrib['connection'].startswith(tuple(prefixes)): 
                    sql = SQL(relation.text)

                    if sql.isCustom() is True:
                        return sql.findTables()
                    else:    
                        print(relation.attrib['table'])
                        return relation.attrib['table']

<datasources>
    <datasource>
        <connection>
            <relation connection="conn.dbe" table="table1">
    <datasource>
        <connection>
            <relation connection="conn.abc" table="table2">

我尝试过使用iterall和findall('.//*relationship')作为匹配模式,但是到目前为止还没有任何结果。