unbound_segments : unbound_terminal FORWARD_SLASH unbound_segments
                            | unbound_terminal

def p_unbound_segments(self, p):
        """unbound_segments : unbound_terminal FORWARD_SLASH unbound_segments
                            | unbound_terminal"""
        p[0] = p[1]
        if len(p) > 2:
            p[0].extend(p[3])