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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 sign(self, xml_doc):
 """Sign the document with a third party signatory. :param str xml_doc: Document self signed in plain xml :returns answer: Answer is given from the signatory itself if connected. """

        try:
            self.client = Client(self.url)
        except ValueError as e:
            self.message = e.message
        except URLError:
            self.message = 'The url you provided: ' + \
                '%s could not be reached' % self.url