Setter for **self.__quotation_markers** attribute.

        :param value: Attribute value.
        :type value: tuple or list

def quotation_markers(self, value):
        """
        Setter for **self.__quotation_markers** attribute.

        :param value: Attribute value.
        :type value: tuple or list
        """

        if value is not None:
            assert type(value) in (tuple, list), "'{0}' attribute: '{1}' type is not 'tuple' or 'list'!".format(
                "quotation_markers", value)
            for element in value:
                assert type(element) is unicode, "'{0}' attribute: '{1}' type is not 'unicode'!".format(
                    "quotation_markers", element)
                assert len(element) == 1, "'{0}' attribute: '{1}' has multiples characters!".format("quotation_markers",
                                                                                                    element)
                assert not re.search(r"\w", element), "'{0}' attribute: '{1}' is an alphanumeric character!".format(
                    "quotation_markers", element)
        self.__quotation_markers = value