xmlparser.Parse(data[, isfinal])

    Parses the contents of the string data, calling the appropriate handler functions to process the parsed data. isfinal must be true on the final call to this method; it allows the parsing of a single file in fragments, not the submission of multiple files. data can be the empty string at any time.

def test(v):
    if v == 0 :
        return 1
    if v == 1 :
        return "Foo"
    if v == 2 :
        return []

for i in xrange(4):
    print type(test(i))

<type 'int'>
<type 'str'>
<type 'list'>
<type 'NoneType'>