def __init__(self, ba, rta_len=None, rta_type=None):
super(rtattr, self).__init__(ba)<EOL>if rta_len is not None:<EOL><INDENT>self.rta_len = rta_len<EOL><DEDENT>if rta_type is not None:<EOL><INDENT>self.rta_type = rta_type<EOL><DEDENT>
Constructor.