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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 _attachment_uri(self, attachid):
 """ Returns the URI for the given attachment ID. """

        att_uri = self.url.replace('xmlrpc.cgi', 'attachment.cgi')
        att_uri = att_uri + '?id=%s' % attachid
        return att_uri