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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def getElementText(self, node, preserve_ws=None):
 """Return the text value of an xml element node. Leading and trailing whitespace is stripped from the value unless the preserve_ws flag is passed with a true value."""

        result = []
        for child in node.childNodes:
            nodetype = child.nodeType
            if nodetype == child.TEXT_NODE or \
               nodetype == child.CDATA_SECTION_NODE:
                result.append(child.nodeValue)
        value = join(result, '')
        if preserve_ws is None:
            value = strip(value)
        return value