Return a circuit with self-feedback from the output port
        (zero-based) ``out_port`` to the input port ``in_port``.

        Args:
            out_port (int or None): The output port from which the feedback
                connection leaves (zero-based, default ``None`` corresponds
                to the *last* port).
            in_port (int or None): The input port into which the feedback
                connection goes (zero-based, default ``None`` corresponds to
                the *last* port).

def feedback(self, *, out_port=None, in_port=None):
        """Return a circuit with self-feedback from the output port
        (zero-based) ``out_port`` to the input port ``in_port``.

        Args:
            out_port (int or None): The output port from which the feedback
                connection leaves (zero-based, default ``None`` corresponds
                to the *last* port).
            in_port (int or None): The input port into which the feedback
                connection goes (zero-based, default ``None`` corresponds to
                the *last* port).
        """
        if out_port is None:
            out_port = self.cdim - 1
        if in_port is None:
            in_port = self.cdim - 1
        return self._feedback(out_port=out_port, in_port=in_port)