findall（）只需要2个参数（给出3个）

Question

这是我的代码：

from elementTree.elementtree.ElementTree import Element, parse, ElementTree

f = open("myxml.xml", 'r')
tree = parse(f)
root = tree.getroot()
f2 = open('out.xml', 'w')

print tree
print root

props = root.findall('property')
print props             

tree.write(f2)

堆栈跟踪：

Traceback (most recent call last):
  File "xmlpy.py", line 11, in <module>
    props = root.findall('property')
  File "D:\user-testing-areas\DWJ\py\elementTree\elementtree\ElementTree.py", li
ne 390, in findall
    return ElementPath.findall(self, path, namespaces)
TypeError: findall() takes exactly 2 arguments (3 given)

我正在按照文档中给出的示例进行操作。

http://docs.python.org/2/library/xml.etree.elementtree.html

我做错了什么？