lxml to parse html

[contro opinion]

    import lxml.html
    myxml='''
    <cooperate>
        <job DecreaseHour="1" table="tpa_radio_sum">
        </job>

        <job DecreaseHour="2"
table="tpa_radio_sum">
        </job>


        <job DecreaseHour="3" table="tpa_radio_sum">
        </job>
    </cooperate>
    '''
    root=lxml.html.fromstring(myxml)
    nodes1=root.xpath('//job[@DecreaseHour="1"]')
    nodes2=root.xpath('//job[@ne_type="101"]')
    print "nodes1=",nodes1
    print "nodes2=",nodes2

what i get is:
nodes1=[]  and
nodes2=[<Element job at 0x13636f0>]
why  nodes1  is  []?nodes2=[<Element job at 0x13636f0>],
it is so strange thing?why ?
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