@staticmethod
def _create_extension(extension):
    """
        Create an ASN.1 certificate request extension structure

        :param tuple extension: tuple with three values: name of the
            extension (str), value for the extension(str), and whether or not
            the extension should be considered critical (bool)
        :return: the extension
        :rtype: dict
        """
    name, value, critical = extension
    return {'extn_id': name, 'extn_value': value, 'critical': critical}
