Wrapper for :class:`.Feedback`, defaulting to last channel

    Args:
        circuit (Circuit): The circuit that undergoes self-feedback
        out_port (int): The output port index, default = None --> last port
        in_port (int): The input port index, default = None --> last port

    Returns:
        Circuit: The circuit with applied feedback operation.

def FB(circuit, *, out_port=None, in_port=None):
    """Wrapper for :class:`.Feedback`, defaulting to last channel

    Args:
        circuit (Circuit): The circuit that undergoes self-feedback
        out_port (int): The output port index, default = None --> last port
        in_port (int): The input port index, default = None --> last port

    Returns:
        Circuit: The circuit with applied feedback operation.
    """
    if out_port is None:
        out_port = circuit.cdim - 1
    if in_port is None:
        in_port = circuit.cdim - 1
    return Feedback.create(circuit, out_port=out_port, in_port=in_port)