XML解析在完成后从列表中删除信息

Question

我使用以下代码来解析XML

from xml.etree.ElementTree import iterparse

# Read xml file
configTree = iterparse('../../SamdConfigurationMainEndat_Hi_LUT.xml', ['start', 'end'])

depth = 0
skipNode = False
parseNodes = ['Actuator', 'Sensor', 'AxisControl', 'ControlNetwork']
level = []
signals = []

for (event, node) in configTree:
    n = n + 1
    if event == 'end':
        if node.tag == 'Alignment':
            skipNode = False
        print(node.tag, signals[-3:-1])
        if node.tag in parseNodes:
            level.pop()
        depth -= 1

    # skip alignment node and only process when node start
    if skipNode is False and event == 'start':
        # check only parseNodes tag and level information
        if node.tag in parseNodes:
            # add elem level information
            if node.get('Name'):
                level.append(node.get('Name'))
            else:
                level.append(node.tag)
            print(depth*'*', node.tag, skipNode, event, level)
        elif node.tag == 'Signal':
            signalValue = {node.get('Name'): node.text}
            elem = [level, signalValue]
            signals.append(elem)            
            print(depth*'=', node.tag, level, signalValue)  
        else:
            print(depth*'+', node.tag)

    if event == 'start':
        if node.tag == 'Alignment':
            skipNode = True
        depth += 1

输出存储在信号列表中。 信号列表的输出不包含级别信息，但在执行代码期间在print语句中可见。

是什么导致关卡信息从信号列表中消失？