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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 readXML(self):
 """ Reads an xml object from the stream. @return: An etree interface compatible object @see: L{xml.set_default_interface} """

        ref = self.readInteger(False)

        if ref & REFERENCE_BIT == 0:
            return self.context.getObject(ref >> 1)

        xmlstring = self.stream.read(ref >> 1)

        x = xml.fromstring(xmlstring)
        self.context.addObject(x)

        return x