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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 _parse(string):
 """ Parses given XML document content. Returns the resulting root XML element node or None if the given XML content is empty. @param string: XML document content to parse. @type string: I{bytes} @return: Resulting root XML element node or None. @rtype: L{Element}|I{None} """

    if string:
        return suds.sax.parser.Parser().parse(string=string)