def canonicalization(self, method, node):
        """
        Canonicalizes a node following the method
        :param method: Method identification
        :type method: str
        :param node: object to canonicalize
        :type node: str
        :return: Canonicalized node in a String
        """
        if method not in constants.TransformUsageC14NMethod:
            raise Exception('Method not allowed: ' + method)
        c14n_method = constants.TransformUsageC14NMethod[method]
        return etree.tostring(
            node,
            method=c14n_method['method'],
            with_comments=c14n_method['comments'],
            exclusive=c14n_method['exclusive']
        )
Canonicalizes a node following the method
        :param method: Method identification
        :type method: str
        :param node: object to canonicalize
        :type node: str
        :return: Canonicalized node in a String